checkerboardpyramid: n stepSize: ss
self north.
i := n.
n timesRepeat: [
	i := i - 1.
	self turnRight: 90.
	(i+1) timesRepeat: [
		4 timesRepeat: 	[
		self go: ss.
		self turnLeft: 90.
		].
		self go: ss.
	].
	self turnLeft: 180.
	self go: ss*(i+1).
	self turnRight: 90.
	self go: ss.
].
self turnLeft: 180. 
self go: ss*n.
self turnLeft: 180.

self north.
i := n.
n timesRepeat: [
	i := i - 1.
	self turnLeft: 90.
	(i+1) timesRepeat: [
		4 timesRepeat: 	[
		self go: ss.
		self turnRight: 90.
		].
		self go: ss.
	].
	self turnRight: 180.
	self go: ss*(i+1).
	self turnLeft: 90.
	self go: ss.
].