function main() returns nothing

number i

for i = 0 to 15

setPenColor(i)

fillBlock(i * 20, (i + 1) * 20)

endfor

endfunction

function fillBlock(number start, number stop) returns nothing

number i

setPenDown()

for i = start to stop

setTurtleXY(0, i)

setAngle(0)

goForward(30)

endfor

endfunction