This figure illustrates a family of octagonal disks with increasing radius of 0, 1, 2, 3, 4 and 5 pixels.
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from morph import *
from Numeric import zeros, arange, shape
r=arange(0,6);
w= 2*r[-1] + 1;
z=mmbinary(zeros((w,w)));
z[shape(z)[0]/2,shape(z)[1]/2]=1;
y=mmbinary([]);
for i in r: o = mmdil(z,mmsedisk(i,'2D','octagon')); y = mmconcat('W',y, o);
mmshow(mmbshow(y,y));