Logo Arts

To New
  # set default screen, pen and turtle values
  ResetAll SetScreenSize [400 400] HideTurtle
  SetSC Black SetPC Green SetPS 1 PenUp
End

To GridSq : Order : Side
  # draw tile at each column x row position
  LocalMake " Offset (1+ : Order )/2
  For (List " Col 1 : Order ) [
    For (List " Row 1 : Order ) [
      SetXY : Side *( : Col - : Offset ) : Side *( : Row - : Offset )
      Tile : Col : Row : Side ] ]
End

To Tile : Col : Row : Side
  # use global value of :Tile to draw selected tile
  Run (Word " Tile : Tile ) : Col : Row : Side
End

To TileBg : Col : Row : Side
  If Even? ( : Col + : Row ) [SetPC [110 110 110]] [SetPC [155 155 155]]
  Square : Side -1 Fill Wait 2
End

To TileCross : Col : Row : Side
  If X>0 [Make " Col : Col +1]
  If Y>0 [Make " Row : Row +1]
  If Even? ( : Col + : Row ) [SetH 90] [SetH 0]
  Cross : Side /2.5 Wait Int : Side /10
End

To Cross : Side
  SetPW : Side /5
  SetPC Black Back : Side /2 PenDown
  Forward : Side PenUp Back : Side /2 Right 90
  SetPC White Back : Side /2 PenDown
  Forward : Side PenUp back : Side /2 Left 90
End

To Square : Side
  # square (side x side) drawn from centre (tp)
  Back : Side /2 Right 90 Back : Side /2 PenDown
  Repeat 4 [
    Forward : Side Left 90]
  PenUp Forward : Side /2 Left 90 Forward : Side /2     # r2c
End

To Even? : Num
  # return 'true' if Num even, else return 'false '
  If (Mod : Num 2)=0 [Output "True] [Output "False]
End

To Go : Order
  New Make " Side Int (400/( : Order +1))
  GlobalMake " Tile " Bg GridSq : Order +1 : Side Wait 20
  GlobalMake " Tile " Cross GridSq : Order : Side
End