A while back, there was an article here “Stacking Cups for the Imagination—A Great Toy Not Found in (Many) Stores”. Simplicity, better play value than many marketed toys, and low cost conspire to limit its shelf space. These are a great first toy.
Babies grow and pretty soon they are in the bathtub, looking for activities. Here, there is another simple toy, foam blocks which float, but also stick to the side of the tube or wall when wet. The blocks themselves are pretty simple. They are just EVA foam cut into different shapes about 2 or 3 inches. As with any blocks, you need a bunch of them to really have a good time.
The possibilities are endless. At the beginning, the kids take delight in just sticking them on the wall. Then the adults can build stick figures, houses, or anything with imagination. Pretty soon, the child is doing it also, and by the end of the toy cycle they are making elaborate structures of their own. (These blocks are sometimes advertised for use on dry land. They do not work out so well there, since there light weight causes the “buildings” to be very unstable, easily knocked over and frustrating to children just learning finer motor skills.)
These foam blocks are not available, at all stores, but are a more often found than the stacking blocks. What is remarkable is wide range in price. Most often, they seem to be sold at a price that averages $1.00/ block (say $20 for a box of only 20). A buck a block seems a little steep, especially in view of what they are. But looking around, some places have them for a price that averages 12 cents a block. A factor of almost 10 times cheaper! Perhaps there is a difference, but both float and stick to the wall!
If it makes bath time more enjoyable, it’s worth a try.