diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 0000000..d0720d7
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,16 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "factoriomod",
+            "request": "launch",
+            "name": "Factorio Mod Debug",
+            "modsPath": "C:/Program Files/Factorio/mods",
+            "configPath": "C:/Program Files/Factorio/config/config.ini",
+            "factorioPath": "C:/Program Files/Factorio/bin/x64/factorio.exe"
+        }
+    ]
+}
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..36e2661
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,50 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to the versioning of Factorio, so 0.18.x will be at least compatible / tested with Factorio 0.18.x.
+
+## [Released]
+
+## [0.18.0] - 2020-06-06
+### General
+- Initial Release of the mod 
+- Compatible with Factorio >0.18.0; tested on 0.18.30
+- Based on the 4-Function Calculator found in the [Max Rate Calculator](https://mods.factorio.com/mod/MaxRateCalculator) mod by [Theanderblast](https://mods.factorio.com/user/theanderblast)
+
+### Added
+- History of recent calculations
+- Possibility to copy recent calculations to the current one (with shift+left-click)
+- Substitutes some functions & "constants" of the Lua [math-lib](http://lua-users.org/wiki/MathLibraryTutorial)
+  - abs() -> math.abs()
+  - acos() -> math.acos()
+  - asin() -> math.asin()
+  - atan() -> math.atan()
+  - ceil() -> math.ceil()
+  - floor() -> math.floor()
+  - cos() -> math.cos()
+  - sin() -> math.sin()
+  - tan() -> math.tan()
+  - deg() -> math.deg()
+  - rad() -> math.rad()
+  - exp() -> math.exp()
+  - log() -> math.log()
+  - min() -> math.min()
+  - max() -> math.max()
+  - modf() -> math.modf()
+  - sqrt() -> math.sqrt()
+  - huge -> math.huge
+  - pi -> math.pi
+- Allows the use of "%" (percent sign) in the calculation
+- A little easter egg :-)
+- Setting for number of decimal places in result (Default: 2). Exact value will be displayed in the tooltip
+- Setting if triggering the calculation should clear the current equation (Default: no)
+
+### Changed
+- Made the buttons slightly bigger, so that it's better readable on streams.
+- Allows to make "complex" calculations with parentheses
+- Allows pretty much all characters in the equation field
+  - but the "=" (equal sign) will trigger the calculation
+
+### Removed
+- Got rid of the memory functions - but introduced the list of recent calculations instead
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..b667143
--- /dev/null
+++ b/README.md
@@ -0,0 +1,26 @@
+# Calculator UI
+
+Calculator UI is a Factorio mod which adds a calculator to the Factorio game with the goal to have a little bit of usability behind it.
+
+## Based on
+The 4-Function Calculator found in the [Max Rate Calculator](https://mods.factorio.com/mod/MaxRateCalculator) mod by [Theanderblast](https://mods.factorio.com/user/theanderblast).
+
+## Features
+- List of recent calculations
+- Use of parentheses in the equation
+- rounding of numbers (number of decimal places can be set in the settings)
+- copy a recent calculation into the current calculation (by shift+left-click on the equation you want to copy)
+- a nifty little easter egg ;-)
+- use of some advanced function and constants of the Lua [math-lib](http://lua-users.org/wiki/MathLibraryTutorial) (without math.) -> e.g. "pi" instead of "math.pi".
+
+## Installation
+Well ... ehm ... search for the mod ingame and install it :-)
+
+## Usage
+Press the 3 little dots on the shortcuts UI of Factorio to select the "Calculator". Afterwards you can click on the calculator symbol to open it.
+
+## Changelog
+see separate [changelog](changelog.md)
+
+## License
+[MIT](https://choosealicense.com/licenses/mit/)
\ No newline at end of file
diff --git a/calculator.lua b/calculator.lua
index 639080b..53263dd 100644
--- a/calculator.lua
+++ b/calculator.lua
@@ -218,8 +218,8 @@ function fix_equation(equation)
 		["tan"]   = "math.tan",
 		["deg"]   = "math.deg",
 		["rad"]   = "math.rad",
-		["exp"]   = "math.log",
-		["exp"]   = "math.log",
+		["exp"]   = "math.exp",
+		["log"]   = "math.log",
 		["min"]   = "math.min",
 		["max"]   = "math.max",
 		["modf"]  = "math.modf",
@@ -292,6 +292,10 @@ function process_equal_key(player, button)
 			end
 		end
 	end
+
+	if settings.get_player_settings(player)["calcui-clear-on-calc"].value then
+		clear_equation(player)
+	end
 end
 
 -- ----------------------------------------------------------------
@@ -390,194 +394,4 @@ function calcui_on_gui_location_changed(event)
 		local root = get_gui_root(player)
 		root.calcui.location = event.element.location
 	end
-end
-
-
-
-
-
-
--- -- ----------------------------------------------------------------
--- local function process_number_key(player, num)
-	-- debug_print("process_number_key(" .. num .. ")")
-	
-	-- if global.calcui_context[player.index].in_left_of_decimal then
-		-- val = num / global.calcui_context[player.index].decimal_place
-		-- if global.calcui_context[player.index].in_data_entry then
-			-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].current_value + val
-		-- else
-			-- global.calcui_context[player.index].current_value = val
-		-- end
-		-- global.calcui_context[player.index].decimal_place = global.calcui_context[player.index].decimal_place * 10
-	-- else
-		-- if global.calcui_context[player.index].in_data_entry then
-			-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].current_value * 10 + num
-		-- else
-			-- global.calcui_context[player.index].current_value = tonumber(num)
-		-- end
-	-- end
-	-- global.calcui_context[player.index].in_data_entry = true
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_decimal_key(player, key)
-	-- debug_print("process_decimal_key(" .. key .. ")")
-	-- if global.calcui_context[player.index].in_left_of_decimal then
-		-- return
-	-- end
-	
-	-- global.calcui_context[player.index].in_left_of_decimal = true
-	-- global.calcui_context[player.index].decimal_place = 10
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_change_sign_key(player, key)
-	-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].current_value * -1
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_equal_key(player, key)
-	-- debug_print("process_equal_key(" .. key .. ")  global.calcui_context[player.index].current_func is " ..  global.calcui_context[player.index].current_func)
-	
-	-- global.calcui_context[player.index].in_data_entry = false
-	-- doing_decimal = false
-		
-	-- if global.calcui_context[player.index].current_func == "ADD" then
-		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand + global.calcui_context[player.index].current_value
-	-- elseif global.calcui_context[player.index].current_func == "SUB" then
-		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand - global.calcui_context[player.index].current_value
-	-- elseif global.calcui_context[player.index].current_func == "MUL" then
-		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand * global.calcui_context[player.index].current_value
-	-- elseif global.calcui_context[player.index].current_func == "DIV" then
-		-- debug_print("process_equal_key global.calcui_context[player.index].current_value " .. global.calcui_context[player.index].current_value)
-	
-		-- if global.calcui_context[player.index].current_value == 0 then
-			-- debug_print("process_equal_key DIVIDE BY ZERO")
-			-- update_display(player, {"calcui_divide_by_zero"}) -- TODO: localize
-			-- return
-		-- end
-		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand / global.calcui_context[player.index].current_value
-	-- end
-	-- global.calcui_context[player.index].current_func = ""
-	-- global.calcui_context[player.index].in_data_entry = false
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_func_key(player, key)
-	-- debug_print("process_func_key(" .. key .. ")")
-
-	-- if global.calcui_context[player.index].current_func ~= "" then
-		-- process_equal_key(player, key)
-	-- end
-		
-	-- global.calcui_context[player.index].current_func = key
-	-- global.calcui_context[player.index].operand = global.calcui_context[player.index].current_value
-	-- global.calcui_context[player.index].in_data_entry = false
-	-- global.calcui_context[player.index].in_left_of_decimal = false
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_mem_key(player, key)
-	-- debug_print("process_mem_key(" .. key .. ")")
-	-- if calculator_memory == nil then
-	    -- debug_print("process_mem_key(" .. key .. ") calculator_memory was nil")
-	    -- calculator_memory = 0
-	-- end
-	-- if key == "MS" then
-		-- calculator_memory = global.calcui_context[player.index].current_value
-	-- elseif key == "M+" then
-		-- calculator_memory = calculator_memory + global.calcui_context[player.index].current_value
-	-- elseif key == "M-" then
-		-- calculator_memory = calculator_memory - global.calcui_context[player.index].current_value
-	-- else
-		-- global.calcui_context[player.index].current_value = calculator_memory
-	-- end
-	-- global.calcui_context[player.index].in_data_entry = false
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_edit_key(player, key)
-	-- debug_print("process_edit_key(" .. key .. ")")
-	-- if key == "CE" then
-		-- global.calcui_context[player.index].current_value = 0
-	-- elseif key == "C" then
-		-- init_calculator(player)
-	-- end
-	-- global.calcui_context[player.index].in_data_entry = false
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function set_current_value_to_text(player, text)
-	-- local last_char = string.sub(text, -1)
-	-- if last_char == "+" then
-		-- process_func_key(player, "ADD") 
-	-- elseif last_char == "-" then
-		-- process_func_key(player, "SUB")
-	-- elseif last_char == "*" then
-		-- process_func_key(player, "MUL")
-	-- elseif last_char == "/" then
-		-- process_func_key(player, "DIV")
-	-- else
-		-- -- number
-		-- local val = tonumber(text)
-		-- if val ~= nil then
-			-- global.calcui_context[player.index].current_value = val
-			-- debug_print("set_current_value_to_text got value " .. text)
-			-- local plain_text = true
-			-- local dot = string.find(text, '.', 1, plain_text)
-			-- if dot ~= nil then
-				-- local number_decimal_places = #text - dot
-				-- global.calcui_context[player.index].decimal_place = 10 ^ (number_decimal_places + 1)
-				-- global.calcui_context[player.index].in_left_of_decimal = true
-				-- debug_print("#text " .. #text .. " number_global.calcui_context[player.index].decimal_places " ..
-					-- number_decimal_places .. " global.calcui_context[player.index].decimal_place " .. global.calcui_context[player.index].decimal_place .. " dot " .. dot .. " in_lod " .. boolstr(global.calcui_context[player.index].in_left_of_decimal))
-			-- else
-				-- debug_print("set_current_value_to_text no dot.  set lod to false" )
-				-- global.calcui_context[player.index].in_left_of_decimal = false
-			-- end
-		-- else
-			-- debug_print("got junk")
-		-- end
-	-- end
--- end
-
--- -- ----------------------------------------------------------------
--- local function process_backspace_key(player, key)
-	-- local root = get_gui_root(player)
-	-- debug_print("process_backspace_key(" .. key .. ")")
-	-- local old_text = root.calcui.calcui_display.caption
-	-- local old_len = #old_text
-	-- text = string.sub(old_text, 1, old_len -1)
-	-- debug_print("process_backspace_key(" .. key .. ") old_text " .. old_text .. " old_len " .. old_len .. " text " .. text .. 
-		-- " in_decimal " .. boolstr(global.calcui_context[player.index].in_left_of_decimal) .. " global.calcui_context[player.index].decimal_place " .. global.calcui_context[player.index].decimal_place)
-	-- if #text == 0 then
-		-- global.calcui_context[player.index].current_value = 0
-	-- else
-		-- set_current_value_to_text(player, text)
-	-- end
-	-- update_display(player)
--- end
-
--- -- ----------------------------------------------------------------
--- local function calcui_toggle_key(event)
-	-- local player = game.players[event.player_index]
-	-- toggle_calculator(player)
--- end
-
--- -- ----------------------------------------------------------------
--- function calcui_clickable_value_clicked(player, val) -- a value in the main Max Rate Calculator has been clicked on.  Paste into current value
-	-- local root = get_gui_root(player)
-	-- if root ~=nil and root.calcui ~= nil then
-		-- local text = tostring(val)
-		-- set_current_value_to_text(player, text)
-		-- update_display(player)
-	-- end
--- end
-
--- script.on_event( "calcui_toggle", calcui_toggle_key )
\ No newline at end of file
+end
\ No newline at end of file
diff --git a/control.lua b/control.lua
index 8acb100..ff6c968 100644
--- a/control.lua
+++ b/control.lua
@@ -28,7 +28,6 @@ end
 
 -- ----------------------------------------------------------------
 local function get_gui_root(player)
-	-- return player.gui.left
 	return player.gui.screen
 end
 
@@ -52,10 +51,7 @@ end
 local function on_gui_click(event)
 	local event_name = event.element.name
 	debug_print("event_name " .. event_name)
-	-- local calcui_prefix = "calcui_"
-	-- local possible_calcui_prefix = string.sub( event_name, 1, string.len(calcui_prefix) )
 	local player = game.players[event.player_index]
-	-- local root = get_gui_root(player)
 	
 	local calcui_prefix = "calcui_"
 	local possible_marcalc_prefix = string.sub( event_name, 1, string.len(calcui_prefix))
@@ -63,25 +59,6 @@ local function on_gui_click(event)
 		handle_calcui_click(event, player)
 		return
 	end
-	
-	-- if possible_calcui_prefix == calcui_prefix then
-		-- if event_name == "calcui_calculator_button" then
-			-- toggle_calculator(player)
-			-- return
-		-- end
-	
-		-- if root.calcui_gui_top then
-		    -- if event_name == "calcui_close_button" then
-				-- destroy_calcui_gui(player)
-				-- hide_calculator(player)
-			-- end
-		-- elseif event_name == "calcui_close_button" then
-			-- if player.gui.left.calcui_gui_top then
-				-- player.gui.left.calcui_gui_top.destroy()
-				-- hide_calculator(player)
-			-- end
-		-- end
-	-- end
 end
 
 -- ----------------------------------------------------------------
@@ -90,9 +67,6 @@ local function on_gui_confirmed(event)
 	player = game.players[event.player_index];
 	if event.element.name == "calcui_display" then
 		process_equal_key(player)
-		if settings.get_player_settings(player)["calcui-enter-clear"].value then
-			clear_equation(player)
-		end
 	end
 end
 
@@ -118,4 +92,4 @@ script.on_event( defines.events.on_gui_click, on_gui_click)
 script.on_event( defines.events.on_gui_confirmed, on_gui_confirmed)
 script.on_event( defines.events.on_gui_text_changed, calcui_on_gui_text_changed )
 script.on_event( defines.events.on_gui_location_changed, calcui_on_gui_location_changed )
-commands.add_command( "calcui", "Max Rate Calculator [ debug | nodebug ] ", on_calcui_command )
\ No newline at end of file
+commands.add_command( "calcui", "Calculator UI [ debug | nodebug ] ", on_calcui_command )
\ No newline at end of file
diff --git a/locale/en/config.cfg b/locale/en/config.cfg
index c511e69..8a90808 100644
--- a/locale/en/config.cfg
+++ b/locale/en/config.cfg
@@ -3,11 +3,11 @@ calcui_4func=Calculator
 
 [mod-setting-name]
 calcui-decimal-places=Decimal places
-calcui-enter-clear=Clear equation on enter?
+calcui-clear-on-calc=Clear equation on calculation
 
 [mod-settings-description]
 calcui-decimal-places=Number of decimal places in the result
-calcui-enter-clear=Should pressing the enter key delete the equation?
+calcui-clear-on-calc=Should trigger the calculation delete the equation?
 
 [calculator-ui]
 title=Calculator
diff --git a/settings.lua b/settings.lua
index 84ce78e..9380ece 100644
--- a/settings.lua
+++ b/settings.lua
@@ -11,7 +11,7 @@ data:extend({
 	{
         type = "bool-setting",
 		default_value = 0,
-        name = "calcui-enter-clear",
+        name = "calcui-clear-on-calc",
         setting_type = "runtime-per-user",
         default_value = false
     }
diff --git a/thumbnail.png b/thumbnail.png
new file mode 100644
index 0000000..cc8449d
--- /dev/null
+++ b/thumbnail.png