# Main Command: GoX
# Tiles by Guy Walker
# www.logoarts.co.uk

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
  LocalMake "Ps [] LocalMake "Total :Order*:Order
  Repeat :Total [Make "Ps LPut RepCount :Ps] 
  Repeat :Total [
    LocalMake "P Pick :Ps
    LocalMake "Ps Remove :P :Ps
    LocalMake "Col 1+Mod :P-1 :Order
    LocalMake "Row 1+Int (:P-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
  SetH Pick [0 90 180 270]     # tile rotation
  SetPC Item (1+Heading/90) [1 2 3 6]
  # SetPC Pick [1 2 3 6]     # comment in for random color
  # SetPC :FlatCol     # comment in for all one color
  GlobalMake "Hue PenColor
  Run Se (Word "Tile :TileNo) 0.95*:Side
End

To Tile1 :Side
  Left 45 Arch 270 :Side/2 Right 45 Back :Side/2
  PenDown Forward :Side/2 Right 90 Forward :Side/2
  PenUp Back 3*:Side/4 SetPC Dark PenColor Fill
  SetPC :Hue Forward :Side/2 Left 90 Arch 180 :Side/4
  Forward :Side/8 SetPC Dark Dark PenColor Fill
End

To Tile2 :Side
  Right 45 Kite 1.414*:Side
  SetPC Dark PenColor Fill PenUp SetPC :Hue
  Right 45 Forward :Side/2 Left 153.4
  PenDown Forward :Side /2.7 Right 36.8 Forward :Side /2.7 PenUp
  Right 150 Forward :Side/4
  SetPC Dark Dark PenColor Fill
End

To Tile3 :Side
  Right 45 Back 1.414*:Side/4 RightAngTri 1.414*:Side
  SetPC Dark PenColor Fill SetPC :Hue
  Right 45 Forward :Side/8 RightAngTri :Side/2
  SetPC Dark Dark PenColor Fill
End

To Tile4 :Side
  Right 45 Lens 1.414*:Side Left 45
  SetPC Dark PenColor Fill
  SetPC :Hue Lens :Side/1.38
  SetPC Dark Dark PenColor Fill
End

To Tile5 :Side
  Right 45 Back 1.414*:Side/2
  SetPC Yellow SetPW :Side/10 Arch 90 :Side/2
  Right 45 SetPW 1 SetPC :FlatCol SetPC Dark PenColor
  PenDown Repeat 4 [
    Forward :Side/4 PenUp Forward :Side/2 PenDown
    Forward :Side/4 Left 90]
  PenUp Forward :Side/2 Left 90 Forward :Side/2
  Repeat 2 [
    Back :Side/2 Arch 180 :Side/4
    Back :Side/2 Arch 68 0.9*:Side Forward :Side
    Back :Side/6 FillZone Forward :Side/6 Left 180]
  SetPC :FlatCol Repeat 2 [
    Back :Side/2 Arch 180 :Side/4
    Back :Side/2 Arch 68 0.9*:Side Forward :Side Left 180]
  Left 135 Back 1.414*:Side/2
  SetPC Yellow SetPW :Side/10 Arch 90 :Side/2 SetPW 1
End

To Tile6 :Side
  SetPC :FlatCol Back :Side/6 Left 90 PenDown
  Forward :Side/2 Left 90 Forward :Side/3
  Left 90 Forward :Side Left 90
  Forward :Side/3 Left 90 Forward :Side/2
  PenUp Forward :Side/6 Right 90 Back :Side/6
  SetPC Dark PenColor Fill Forward :Side/6
  SetPC Yellow PenDown Forward :Side/6 PenUp
  Forward :Side/6 Circle :Side/6 SetPC Orange Fill
End

To Tile7 :Side
  If Or (Heading =90) (Heading=270) [Right 26.5] [Right 63.5]
  Square 0.74*:Side Back 0.37*:Side PenDown
  Forward 0.37*:Side Right 90 Forward 0.37*:Side
  PenUp Back :Side/2 SetPC Dark PenColor Fill
  Right 30 Forward :Side/3
  SetPC Dark PenColor Fill
End

To Tile8 :Side
  Chevron :Side Chevron :Side/2
  Forward 3*:Side/8 SetPC Dark PenColor Fill
  Back :Side/4 SetPC Dark PenColor Fill
End

To Tile9 :Side
  Right 45 Back 1.414 *:Side/6 Left 45 Square 2*:Side/3
  SetPC Dark PenColor Fill SetPC :Hue
  Forward :Side/3 PenDown Forward :Side/3
  Right 45 Back 1.414 *:Side/3 PenUp Forward 1.414 *:Side/3
  PenDown Right 45 Forward 2*:Side/3 Right 90 Forward 2*:Side/3
  Right 45 Forward 1.414 *:Side/3 PenUp
  Right 135 Forward 2*:Side/3 Right 45 PenDown Forward 1.414 *:Side/3
  PenUp Right 135 Forward :Side/6 Right 90 Forward :Side/12
  SetPC Dark Dark PenColor Fill Forward 2*:Side/3 Fill
  Back :Side/6 SetPC Dark PenColor Fill
End

To Tile10 :Side
  Back :Side/2 Right 90 Back :Side/2
  PenDown Forward :Side Left 90 Forward :Side
  Left 90 Forward :Side/3 Left 90 Forward 2*:Side/3
  Right 90 Forward 2*:Side/3 Left 90 Forward :Side/3
  PenUp Back :Side PenDown Repeat 4 [
    Forward :Side/3 Left 90] PenUp
  Left 45 Forward 1.414*:Side/6 SetPC Dark Dark PenColor Fill
  Forward 2*1.414*:Side/3 SetPC :Hue SetPC Dark PenColor Fill
End

To Tile11 :Side
  Right 90 Forward :Side/3 Left 90 Forward :Side/6
  Repeat 2 [
    SetPC Dark Dark PenColor
    FillPolygon [PD (Pgram :Side/3 2*:Side/3 Minus 1)]
  SetPC :Hue (Pgram :Side/3 2*:Side/3 Minus 1)
  Left 90 Forward :Side/2 Left 90
  SetPC Dark PenColor FillPolygon [PD Pgram 2*:Side/3 2*:Side/3]
  SetPC :Hue Pgram 2*:Side/3 2*:Side/3
  Right 90 Forward :Side/6 Left 90 Forward :Side/3]
End

To Tile12 :Side
  Left 90 Forward :Side/4 Right 90 Forward :Side/4
  Repeat 2 [
    SetPC Dark Dark PenColor FillPolygon [PD Pgram :Side/2 :Side/2]
  SetPC :Hue Pgram :Side/2 :Side/2 Right 90 Forward :Side/2 Right 90
  SetPC Dark PenColor FillPolygon [ PD (Pgram :Side/2 :Side/2 Minus 1)]
  SetPC :Hue (Pgram :Side/2 :Side/2 Minus 1) Forward :Side/2]
End

To GoX
  Forever [Go (1+Random 12) (4+Random 5) Wait 240]
End

To Go :Tile :Order
  New Make "Side Int 380/:Order     # screen width 380
  GlobalMake "TileNo :Tile
  GlobalMake "FlatCol Pick [4 6 9 15]     # flat color for tiles 5 and 6 
  If :Order<6 [SetPW Abs (7-:Order)]     # fat pen for low orders
  GridSq :Order :Side
End

To Arch :Angle :Radius
  # symmetrical arc drawn relative to turtle heading
  Arc :Radius Heading-:Angle/2 Heading+:Angle/2
End

To Chevron :Size
  # chevron shape drawn from centre (tp)
  PenDown Left 45
  Forward 1.414*:Size/2 Right 135 Forward :Size/2
  Right 45 Forward 1.414*:Size/2 Right 90 Forward 1.414*:Size/2
  Right 45 Forward :Size/2 Right 135 Forward 1.414*:Size/2
  Left 45 PenUp
End

To Kite :Size
  # kite shape drawn from centre (tp)
  Back :Size/2 PenDown
  Left 18.4 Forward :Size/1.26 Right 63.4
  Forward :Size/2.82 Right 90 Forward :Size/2.82
  Right 63.4 Forward :Size/1.26
  PenUp Right 161.6 Forward :Size/2     # return to centre
End

To Lens :Size
  # lens shape drawn from centre (tp)
  Repeat 2 [
    Back :Size/2 Arch 90 :Size/1.414
    Forward :Size/2 Left 180]
End

To Pgram :Wide :High [:P 1]
  # parallelogram shape drawn from centre (tp)
  # default parity of 1, use minus 1 for mirror image
  LocalMake "Ang ATan :Wide/(:High/2)     # inner angle
  LocalMake "Len :Wide/ Sin :Ang     # side length
  Back :High/4 Right :P*:Ang Back :Len/2 PenDown
  Repeat 2 [
    Forward :Len Left :P*:Ang Forward :High/2 Left :P*(180-:Ang)]
  PenUp Forward :Len/2 Left :P*:Ang Forward :High/4     # r2c
End

To RightAngTri :Size
  # right angled triangle drawn from centre (tp)
  Back :Size/4 Right 45
  PenDown Forward 1.414*:Size/2
  Left 135 Forward :Size
  Left 135 Forward 1.414*:Size/2 PenUp
  Left 135 Forward :Size/4     # return to centre
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 Dark :Hue
  # output rgb list midway between :hue and black
  Repeat 3 [
    Make "Hue ButFirst LPut Int (First :Hue)/2 :Hue]
  Output :Hue
End