procedure figure1a()
   local S

   S := sconcat(
      srun(1, 4),
      srun(1, 5),
      srun(2 ,6),
      srun(3, 6),
      srun(3, 7),
      srun(4, 8),
      srun(5, 8),
      srun(5, 7),
      srun(4, 6),
      srun(3, 6),
      srun(3, 5),
      srun(2, 4)
      )

   retrun sconcat(srun(1, 4), srepeat(S, 3))

end

procedure figure1b()
   local S

   S := sconcat(
      srepeat(srun(1, 2), 3),
      srepeat(srun(3, 2), 2),
      srepeat(srun(3, 4), 3)
      )

   return srepeat(S, 11)

end

procedure figure1c()
   local S, T, U, V, W

   S := srun(1, 2)

   U := sconcat(6, srun(1, 3))

   V := sconcat(1, 4, 2, 3)

   W := sconcat(1, 2, 6)

   T := sconcat(
      U,
      V,
      6,
      V,
      srepeat(W, 5),
      srun(1, 3),
      V
      )

   return  sconcat(srepeat(S, 25), srepeat(T, 3))

end

procedure figure1d()
   local S, T

   S := sconcat(
      scpal(srun(8, 5)),
      srun(7, 2),
      scpal(srun(1, 4)),
      srun(8, 1)
      )

   T := sconcat(
      srun(1,3),
      scpal(S),
      srun(1,4)
      )
 
   return sopal(T)

end

procedure figure1e()
   local S, T, U

   S := srun(1, 8)

   T := scpal(S)

   U := sreflectv(T)

   return scpal(
      sconcat(
         T,
         U,
         srepeat(S, 2),
         srepeat(srun(5, 8), 2)
         )
      )

end