local sideHeight = 35
local width = 55
local topHeight = 20
local polys = {
   {
      0, 0, width/2, topHeight/2,
      0, topHeight, -width/2,  topHeight/2,
   },
   {
      0, topHeight, width/2, topHeight/2,
      width/2, topHeight/2 + sideHeight, 0, topHeight + sideHeight,
   },
   {
      0, topHeight, -width/2, topHeight/2,
	 -width/2, topHeight/2 + sideHeight, 0, topHeight + sideHeight,
   },
}




return function(size, discs, topCol, rightCol, leftCol)
   assert(size > 0)
   for disc in pairs(discs) do
      assert(disc >= -size and disc <= size)
   end

   local colours = {topCol, rightCol, leftCol}   
   local function drawCube(x, y)
      love.graphics.push()
      love.graphics.translate(x, y)
      for ix, poly in ipairs(polys) do
	 love.graphics.setColor(colours[ix])
	 love.graphics.polygon("fill", poly)
      end
      love.graphics.pop()
   end

   local function getHeight()
	 return size*(topHeight/2 + sideHeight) + topHeight/2
   end

   local x = love.graphics.getWidth()/2
   local y = love.graphics.getHeight()/2 - getHeight()/2;

   local function qpos2Coords(se, sw)
      return x + se * width/2 - sw * width/2,
	 y + (se + sw)*(topHeight/2+sideHeight)
   end

   return {
      getDepth = function() return -1; end,
      
      getWidth = function()
	 return size*width*2
      end,
   
      getHeight = getHeight,

      getSize = function() return size; end,
      getCubeSideHeight = function() return sideHeight; end,
      getCubeTopHeight = function() return topHeight; end,
      getCubeHeight = function() return sideHeight+topHeight; end,
      getCubeWidth = function() return width; end,
      getRowHeight = function() return sideHeight+topHeight/2; end,
      getColWidth = function() return width/2; end,
      qpos2Coords = qpos2Coords,
      
      draw = function()
	 for se = 0, size-1 do
	    for sw = 0, size-1 do
	       if (se + sw < size) then
		  local x, y = qpos2Coords(se, sw)
		  drawCube(x, y)
	       end
	    end
	 end
      end,
      
      update = function(dt)
      end,
   }
end