How to make a stained glass window

Sit on a comfortable stool at a spacious workbench.
Think of light and color and never of stains.
Have everything to hand.
Keep pictures in your head.
Let the light in.

Take molten rubies and pour between strips of cold lead.
Dab emerald magma here and there,
Use sapphires sparingly.
Let the light in.

Think of religious purpose.
Stop thinking of religious purpose.
Think of saints and sinners.
Think of harmony and horror.
Let your thoughts inform your work.
Let the pictures out of your head.
Let the light in.

Let in the light.

(This poem was originally published in De-seeded Vol. 3 edited by Degna Stone)