Connections are important, whether it's between people or between shiny pixelated blocks. You can make one hundred and twenty levels of connections in Retrocade's puzzler Linx, along with its expansion packs Linx: Easy Set and Linx: Hard set. You might connect the concept with the well-received 3D Logic series of spatial logic games. This one is just in a 2d package. And the game's developers have even sought to make connections with the colorblind community by including a colorblind mode! Are you feeling warm and fuzzy connections to all of life yet? Because you should be.
Pick a color (or a texture in colorblind mode) by clicking on a node, then click or click and drag to draw lines with that color. You can also select an "eraser" mode on the left or hold the [spacebar] while clicking to erase lines. This button can also be changed in the options. The idea is to connect all nodes of the same color without any differently colored lines crossing each other. That is, every tile contains either one color or no colors.
The easy set is so easy that experienced spatial logic fans will probably want to skip straight to the hard. In some levels, the trick is figuring out how to connect the rainbow of different nodes without anyone getting boxed in by other colors. The game calls these levels "routing" levels. In other levels, you're only dealing with one color but you have an extremely limited number of tiles. The game calls these "limiting" levels. The switch-off between the two different types helps keep the player stimulated since they call for different strategies. The interface is simple and extremely intuitive and user-friendly. The only potential drawback is that you have to solve the puzzles strictly in order, so if, for example, you prefer the routing type to the limiting type, you can't just skip the kind you don't like. But both types are likely to appeal to the same kind of player, so connect with your inner genius and play away.