Figures were created by running xgrow and using the EXPORT feature, 
then loading the tile arrangement into Matlab as a matrix, and running
a script to generate a PostScript file.

Fig. 2a:  xgrow sierpinski_diag_noseed_preborder T=2 

Fig. 2b:  xgrow sierpinski_diag_noseed_preborder Gmc=17 Gse=8.8 addflakes=128,128,1:20

Fig. 2c:  xgrow sierpinski_diag-symmetric-slowborder Gmc=17 Gse=8.6 addflakes=128,128,1:20
   Simulations in Supplementary Fig. 1ab used the same tile set and parameters.

Fig. 2d:  xgrow XOR Gmc=25 Gse=18
   Using the GUI, the simulation was run until an assembly spontaneously nucleated and
   grew to roughly 20x20 tiles.  Then Gse was reduced to 12.7 to encourage dissociation
   of erroneous tiles; the simulation was paused when a roughly 10x10 tile assembly with
   no errors was obtained.  Gse was increased to 13 and the simulation continued until
   the roughly 65x65 error-free assembly was obtained. 

Fig. 2e:  xgrow XOR Gmc=17 Gse=10.4
   The simulation was stopped when a roughly 65x65 assembly was obtained. 

Fig. 2f:  xgrow XOR-symmetric Gmc=17 Gse=10.4
   Using the GUI, the simulation was run until an assembly spontaneously nucleated and
   grew to roughly 20x20 tiles.  Then Gse was reduced to 8.4 to encourage dissociation
   of erroneous tiles; the simulation was paused when a roughly 10x10 tile assembly with
   no errors was obtained.  Gse was increased to 8.6 and the simulation continued until
   a roughly 65x65 assembly was obtained. 

Supplementary Fig. 1c: xgrow XOR-symmetric Gmc=17 Gse=10.4 block=10 size=64 seed=32,32,1
   Using the GUI, the simulation was stopped at size approximately 2000 tiles.