diff --git a/checkbox.lua b/checkbox.lua
new file mode 100644
index 0000000..ca2737a
--- /dev/null
+++ b/checkbox.lua
@@ -0,0 +1,46 @@
+local Checkbox = {}
+Checkbox.__index = Checkbox
+
+function Checkbox:new(width, lineWidth, transform, checked)
+  local box = {
+    width = width or 20,
+    lineWidth = lineWidth or 2,
+    transform = transform or love.math.newTransform(),
+    checked = checked,
+    onChanged = nil
+  }
+  return setmetatable(box, self)
+end
+
+function Checkbox:draw()
+  local width = self.width
+  local lineWidth = self.lineWidth
+  local halfLine = lineWidth/2
+  local boxWidth = width - lineWidth
+  love.graphics.push("all")
+  love.graphics.applyTransform(self.transform)
+  love.graphics.setLineWidth(lineWidth)
+  love.graphics.rectangle("line", halfLine, halfLine, boxWidth, boxWidth)
+  if self.checked then
+    local crossEnd = width - halfLine
+    love.graphics.line(halfLine, halfLine, crossEnd, crossEnd)
+    love.graphics.line(halfLine, crossEnd, crossEnd, halfLine)
+  end
+  love.graphics.pop()
+end
+
+function Checkbox:getChecked()
+  return self.checked
+end
+
+function Checkbox:pressmouse(x, y, button)
+  if button == 1 then
+    local localX, localY = self.transform:inverseTransformPoint(x, y)
+    if localX >= 0 and localX < self.width and localY >= 0 and localY < self.width then
+      self.checked = not self.checked
+      if self.onChanged then self.onChanged(self.checked) end
+    end
+  end
+end
+
+return Checkbox
\ No newline at end of file
diff --git a/main.lua b/main.lua
index 8a8f9de..033994b 100644
--- a/main.lua
+++ b/main.lua
@@ -1,11 +1,10 @@
 
 local Time = require"time"
 local Clock = require"clock"
+local Checkbox = require"checkbox"
 
 function love.load()
   if arg[#arg] == "-debug" then require("mobdebug").start() end
-    
-  local fontsize = love.graphics.getHeight() / 20
   
   local margin = love.graphics.getHeight() / 20
   
@@ -21,21 +20,49 @@ function love.load()
   end
 
   local exitNote = "Press \"Esc\" to exit."
-  local exitNoteWidth = love.graphics.getWidth() - column2X - margin
-  local exitNoteFont = love.graphics.newFont(fontsize)
-  local _, wraps = exitNoteFont:getWrap(exitNote, exitNoteWidth)
-  local exitNoteY = love.graphics.getHeight() - table.maxn(wraps) * exitNoteFont:getHeight() - margin
+  local column2Width = love.graphics.getWidth() - column2X - margin
+  local font = love.graphics.newFont(love.graphics.getHeight() / 20)
+  
+  local _, exitNoteWraps = font:getWrap(exitNote, column2Width)
+  local exitNoteY = love.graphics.getHeight() - table.maxn(exitNoteWraps) * font:getHeight() - margin
+  
+  local checkboxSize = font:getBaseline()
+  local checkboxLine = love.graphics.getHeight()/180
+  local checkbox = Checkbox:new(checkboxSize, checkboxLine, love.math.newTransform(column2X, margin), false)
+  local showTime = checkbox.checked
+  checkbox.onChanged = function(checked)
+    showTime = checked
+  end
+  
+  local textCanvas = love.graphics.newCanvas(love.graphics.getWidth(), love.graphics.getHeight())
+  love.graphics.setCanvas(textCanvas)
+  love.graphics.setColor(1,1,1)
+  love.graphics.printf(" Show time", font, column2X + checkboxSize + checkboxLine, margin, column2Width)
+  love.graphics.printf("Press \"Esc\" to exit.", font, column2X, exitNoteY, column2Width)
+  love.graphics.setCanvas()
+  
+  local timeString
+  local timeIndent
+  local figureWidth = font:getWidth("0")
+  clock.onSetHands = function(t)
+    timeString = tostring(clock:getTime())
+    if #timeString < 5 then
+      timeIndent = figureWidth
+    else
+      timeIndent = 0
+    end
+  end
+  clock.onSetHands(clock:getTime())
   
   love.graphics.setBackgroundColor(0.02,0.53,0.77)
   
-  
   function love.mousemoved(x, y, dx, dy, istouch)
     clock:movemouse(x, y)
   end
 
-  -- todo mousepressed & mousereleased
   function love.mousepressed(x, y, button, istouch, presses)
     clock:pressmouse(x, y, button)
+    checkbox:pressmouse(x, y, button)
   end
 
   function love.mousereleased(x, y, button, istouch, presses)
@@ -44,7 +71,11 @@ function love.load()
 
   function love.draw()
     clock:draw()
-    love.graphics.printf(exitNote, exitNoteFont, column2X, exitNoteY, exitNoteWidth)
+    checkbox:draw()
+    love.graphics.draw(textCanvas, 0, 0)
+    if showTime then
+      love.graphics.printf(timeString, font, column2X+timeIndent, margin+font:getHeight(), column2Width)
+    end
   end
 end
 
diff --git a/time.lua b/time.lua
index b46aa73..606b7b4 100644
--- a/time.lua
+++ b/time.lua
@@ -33,7 +33,7 @@ end
 
 function Time:__tostring()
   local h, m = self:get()
-  return string.format("%2d:%02d", h, m)
+  return string.format("%d:%02d", h, m)
 end
 
 return Time