%Assuming printing cube of 100 layers with a 20 layer pipe in the middle
for $z = 1 to 39 step 1
	print square layer
end

for $z = 40 to 60 step 1
	print square layer
	print bottom half of pipe
	print top half of pipe
end

for $z = 61 to 100 step 1
	print square layer
end