// staircase from 2C (split into two parts)
paper 10
command staircase
{
   command darktrap m n o
   {
      line n m (n+5) (m+10)
      line n m o m
      line o m (o+5) (m+10)
      line (n+5) (m+10) (o+5) (m+10)
   }

   command lighttrap f g h
   {
      line (g+5) f (h+5) f
      line (g+5) f g (f+10)
      line (h+5) f h (f+10)
      line h (f+10) g (f+10)
   }

   pen 60
   repeat m 60 90
   {
      darktrap 8 m 90
   }
   pen 60
   repeat m 60 90
   {
      darktrap 28 m 90
   }
   pen 60
   repeat m 20 50
   {
      darktrap 48 m 90
   }
   pen 60
   repeat m 20 50
   {
      darktrap 68 m 90
   }
   pen 40
   repeat m 60 90
   {
      lighttrap 18 m 90
   }
   pen 40
   repeat m 60 90
   {
      lighttrap 38 m 90
   }
   pen 40
   repeat m 20 50
   {
      lighttrap 58 m 90
   }

   pen 40
   repeat m 20 50
   {
      lighttrap 78 m 90
   }
}

staircase

// geometric progression from 3A
command geoprog
{
   repeat a 50 75
   {
      pen 20
      line 50 a 100 a
   }

   repeat a 75 100
   {
      pen 25
      line a 75 a 100
   }

   repeat a 50 75
   {
      pen 30
      line a 88 a 100
   }

   repeat a 50 63
   {
      pen 40
      line a 75 a 88
   }

   repeat a 81 88
   {
      pen 35
      line 63 a 75 a
   }

   repeat a 81 88
   {
      pen 45
      line 63 a 75 a
   }

   repeat a 63 69
   {
      pen 50
      line a 75 a 81
   }

   repeat a 69 75
   {
      pen 55
      line a 75 a 81
   }

   pen 100

   line 50 50 50 100
   line 50 75 100 75
   line 75 75 75 100
   line 50 88 75 88
   line 63 75 63 88
   line 63 81 75 81
   line 69 75 69 81
}

geoprog

//bar from 2C
command bar
{
   pen 75
   repeat t 15 20
   {
      line t 0 t 100
   }
}

bar

//squares from 1C
command squares
{
   repeat x 10 60
   {
      pen x
      line x 0 x 50
      line x 50 x 50
      line x 50 x 50
      line x 0 x 50
   }
   {
      repeat x 0 25
      {
         pen 50
         line x 0 x 25
         line x 25 x 25
         line x 25 x 0
         line x 0 x 25
      }
   }
}

squares

pen 100
line 50 50 100 50
line 50 49 100 49

//fan from 2C, slightly different in size
command fans
{
   command fan c d
   {
      pen 100
      line 50 50 c d
      line 50 50 (c+5) (d-1)
      line 50 50 (c+10) (d-3)
      line 50 50 (c+15) (d-5)
   }
   fan 1 35
   fan 45 5
   fan 10 7
}

fans