A single fold pattern

Use very thin coloured paper.
Fold each circle once to the centre.
Overlap the
second circle so that ends of chords meet
and edge of second circle lies on the centre of the first circle.

Add more circles in this way.

When you have six folded circles in place they will make a hexagon.
Glue the circles in place.
When the hexagon is placed against the light
this pattern emerges.
Combining many of these hexagons on the window creates this pattern.

See Hints on How to Display Window
Patterns
Glue to a piece of clear plastic such as non adhesive book covering
film and place on a window.