It's tied up with a lot of happy memories - it was one of the first Grimm's toys we brought into The Happy Lark. I remember being so excited to place an order, as we'd been wanting to stock Grimm's since we first opened but had to wait until they were accepting new shops.
It was also the first Grimm's toy I bought for my daughter. We gave it to her on her 2nd birthday and immediately starting having fun with it. At this age, we enjoyed setting up tunnels together and then she'd practice rolling her cars through.
As she got closer to 3 years, she began doing more open ended, pretend play with it. According to her imagination, this picture is of "three bathtubs and four chairs" she made.
The rainbow can also mix and match with her other toys. Today, we made a "dinosaur mountain."
Basically, it's the perfect toy. It's beautiful. Durable. Encourages open ended and creative play. Encourages building and problem solving. Can be played with in different ways as she gets older. Plays well with other toys. What more can you ask for from a toy?