Open plastic cubes in increasing sizes. Slide them into one another into a compact block that takes up little room, or turn them over and build them from large to small into a tower that your child will then happily knock down.
The set comes with stickers to put on the sides: numbers on one side, groups of fruit on the other - apples, strawberries, oranges and bananas. That turns the same toy into something else later on. First it is stacking and toppling, then counting and matching the right number to the right quantity.
The box puts it well itself: build a tower and learn new words, numbers and colours along the way. The blocks increase in size, so they nest neatly when it is time to tidy up. The packaging says 12m+, so from 12 months.
One of those toys a toddler gets months out of, because it grows along from stacking to counting. Playgo, item number 2382.