The larger stones were just aggregate got from a load that my brother had
to do some building work and the smaller grit was from an old bag of
mixed gravel I found round the back at where I used to work.
The 'stained glass' windows are just 20 thou clear styrene, the shapes drawn
with marker pen to no specific design, coloured marker pens used for the individual areas.
A few holes knocked through and cracks added.

The glass shards are the same plastic sheet just coloured and then cut up and
liberally spread about the place, there you have it.