Transmission is a game about optimization. You get a bunch of nodes that can either receive or pass on traveling cubes. You send about cubes by linking the nodes in an efficient manner. Thoroughly simple at the beginning, but fairly difficult towards the end.
Transmission is designed to teach a little about the history of telecommunications. Each chapter talks about one form or other, such as the telegraph or the broadcast network, but it also introduces a new node type and accompanying mechanic, making the levels more interesting overall.
The clean graphics and sound make for a very pleasurable experience, while the level themselves can be completed hastily or with efficiency in order to get a set amount of stars, which will eventually unlock high tier levels. This mechanic is very smart because it forces you to think creatively and really understand how to solve a level in Transmission before you're allowed to crunch your brain at another more difficult one.
I really liked Transmission and I quite wonder why I didn't find it before.