# Main Command: Go 7
# Oct 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 Init :Order
  # initialise parameters
  Make "Width 380
  Make "CellSize :Width/:Order
  Make "Half :CellSize/2
  Make "Offset (:Width-:CellSize)/2
  Make "Dist :Half/Cos 22.5
  Make "Points Shuffle [0 1 2 3 4 5 6 7]
End

To Gridd :M :N
  # return X Y screen position
  Make "X (:N*:CellSize) - :OffSet
  Make "Y (:M*:CellSize) - :OffSet
  Output List :X :Y
End

To DrawGrid :Order
  # draw M x N array of cubes
  For (List "M 0 :Order-1) [
    For (List "N 0 :Order-1) [
      SetPos Gridd :M :N
      Tile] ]
End

To Tile
  # connect 4 pairs of 8 points
  Make "PosC Pos
  Make "Points Shuffle [0 1 2 3 4 5 6 7]   # comment out for overall
  Repeat 4 [
    SetPos :PosC SetH 0
    Path Item ((RepCount*2)-1) :Points Item (RepCount*2) :Points]
End

To Grout :Size :Order
  # draw centred square grid with :order divisions
  SetPC [64 64 64] SetPW 1
  For (List "Point 0 :Size+1 :Size/:Order) [
    SetXY :Point-:Size/2 :Size/2 SetH 180
    PenDown Forward :Size PenUp
    SetXY :Size/2 :Point-:Size/2 SetH 270
    PenDown Forward :Size PenUp Wait 2]
End

To Path :A :B
  # draw line or curve between points a and b
  Make "Diff Abs (:A-:B)
  SetH 202.5 +45*((:A+:B)/2)
  If :Diff=4 [
    Right 90 Forward :Dist Left 180 PenDown Forward 2*:Dist PenUp Stop]
  If :Diff >4 [Make "Diff 8-:Diff Left 180]
  Back :Dist/Cos (:Diff*22.5) Arch 180-(:Diff*45) :Dist*Tan (:Diff*22.5)
End

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

To Shuffle :myList
  # randomly shuffle list order
  LocalMake "Shuffled [ ] 
  Repeat Count :myList [
    LocalMake "Select Pick :myList
    Make "myList Remove :Select :myList
    LocalMake "Shuffled LPut :Select :Shuffled]
  Output :Shuffled
End

To Info
  SetPC White SetFontJustify [1 1]
  Home Label :Points 
  Repeat 8 [
    Home SetH (RepCount*45)-20
    Forward 190 SetH 0 Label RepCount-1]
End

To Go :Order
  New Init :Order
  DrawGrid :Order
  # SetPC DarkRed SetPos [198 198] Fill  # comment in
  If :Order <7 [Grout :Width :Order]
  If :Order =1 [Info]
End