This was a quiet, low-fuss activity I did with a group of 6 children (aged 2.5 - 4.5). I gave them access to some sheets of stationary dot stickers in various colours and sizes, and some cut up sheets of translucent coloured contact (self sticking plastic).
I gave them some coloured cardboard to work on and some drawing implements to work into their artwork if they wanted. Every child had their own way of working with the stickers- some overlapping, some very ordered, some random.
Two boys made 'laptop computers' by folding the cardboard in half and using the dots as keyboard and the contact as the computer screen. They then played 'games' with their laptops set up on a table.