lumen., from Lykkegaard Europe Limited, is a puzzle game played on a small grid (varies in size but 6x10 seems the biggest). Object is to get light emitters to trace their lights to end points, and over the three optional stars on the grid. There are one-sided and two-sided mirrors you can rotate to guide the light beams (and you can rotate the emitters).

Higher levels have double emitters (fixed to emit at opposite sides or two adjacent sides), four-way emitters (light in all four directions), rotatable pipe (which blocks light vertically or horizontally), T-pipes (which split an incoming beam into two beams), squares that block light, and probably others.

There is a daily challenge of four puzzles. There is a weekly maze challenge where your one beam navigates a maze to the end point. Lots of achievements. A bit of a backstory about a female inventor creating these various gadgets and the box you play on unlocks her journals. Lots of puzzles, maybe 300-plus.

Overall I had fun playing the first couple hundred puzzles and I guess that's enough for me.