X Construction Lite
Building a better train bridge

The premise of the game X Construction lite is simple: Build a bridge across a large ditch that’s stable enough to keep a train from plummeting into the depths. Players are given a limited amount of girders to complete the task, which can be harder than you think. The girders aren’t fixed, so the game requires some basic engineering skills to keep the train on track. The touchscreen controls can be a imprecise and annoying, sometimes leading you to remove a vital point by accident. Still, the game is quite addictive and good for those times when you need a little brainteaser in between meetings or on the bus.

The lite version has 15 levels and three difficulty settings. Free, for Android.

— Hayley Tsukayama