Make a giant kaleidoscope
Three large mirrors (~30x120cm) per kaleidoscope made (in NZ the Warehouse has these available for $10 each).
Packing tape or duct tape
Large (~1m square) piece of clear plastic
Coloured permanent markers
Form mirrors into a triangular prism shape with reflective surfaces on inside and join with tape. Easiest way to do this is to lie mirrors with reflective surface down side by side and 1-2cm gap between each mirror then tape together. Then turn and fold into triangle and tape final edge together.
Make a small hole large enough to look through in the centre of your piece of cardboard.
Tape cardboard to one end of triangular prism - this will be your viewer.
Colour clear plastic with multicoloured designs (large spots work well in bolder colours) then hold this against the other end, covering it and move it while someone looks through the other end.