I didn't think we were going to get any of it done as Matthew made a beeline for the clay (as usual), but eventually I managed to tempt him over to look at the marbling tray and that got him hooked.
The boxes are just folded paper (here is a step-by-step tutorial, which uses the same technique). The large one is decorated with collage, the medium one is marbled, and Matthew drew on the small one with crayons.
Inside the large box is a butterfly made from tissue paper, netting and pipe cleaners; there is a woolly pipe cleaner spider in the middle box; and the two bees in the smallest box are made from netting wings glued onto tiny pine cones wrapped round with yellow wool.
The most amazing thing - apart from the fact that we actually got them all made (with time to SPARE even) - is that these are all still intact (so far). Matthew likes opening them, saying hello to the little creatures, then closing them again carefully and going on his way. Unprecedented.