aUCBLogo Demos and Tests / stairs

to stairs [size 150]      ; draws stairs in 3D mode
   cs perspective
   enableCylinderLines
;   hideTurtle
   pu setxyz 0 -2/3*size size pd
   setpensize [3 3]
   switch_back
   rotateScene
end

to half_round_landing
   down 90
   rt 90
   arc -180 size
   rt 90
   up 90
end

to quarter_round_landing
   down 90
   arc 90 size
   lt 90
   up 90
end

to stair_rise
   repeat 2 [fd size/6 rt 90 fd size rt 90]
   fd size/6
end

to stair_run
   repeat 2 [fd size/3 rt 90 fd size rt 90]
   fd size/3
end

to stair_step
   stair_rise
   down 90
   stair_run
   up 90
end

to switch_back
   setpc 0
   repeat 3 [stair_step] quarter_round_landing
   setpc 1
   repeat 3 [stair_step] half_round_landing
   setpc 2
   repeat 3 [stair_step]
end