Compiled a.osl -> a.oso
Compiled b.osl -> b.oso
Connect alayer.out to blayer.in
a start, Ci = ''
a end, Ci = '(1, 0, 0) * emission ()'
b start, Ci = '(1, 0, 0) * emission ()'
b end, Ci = '(0, 1, 0.5) * emission ()'

