Happy Glass — Draw a Line, Fill the Glass

Happy Glass: a physics puzzle where your pencil is the only tool

Happy Glass starts every level the same way: a glass with a sad face, a dotted line showing how full it needs to be, and a tap that is about to open. What sits between them changes every time — a gap, a shelf, a spinning wheel, a second glass in the way, or a glass lying on its side. You have a pencil and a fixed amount of ink. Whatever you draw turns solid the moment you let go and falls under gravity like everything else in the level, so a line can be a ramp, a plug, a lid, a lever or a counterweight, depending on where you put it. When the water reaches the mark, the glass smiles and the level is done.

The ink bar is where the game lives. Any line that gets the water in will clear the level, but the three-star score is only paid if you stayed under the red mark on the bar, and the quickest solution is rarely the first one you think of. Later levels add pipes, movable platforms and glasses that have to be knocked upright before they can hold anything, and the hardest ones need the line to be drawn in one careful shape so it lands where you meant. Classic mode runs to 688 levels, and three variants — Don't Spill, Flippy Glass and Precise — unlock as you get further in. The build on happyglass.me is the Unity web version, served from this domain, with the same levels and the same star rules as the mobile game.

Controls & mechanics

Getting three stars in Happy Glass

1. Draw the shortest ramp that works: Ink is the score. A short diagonal from the tap to the rim of the glass usually beats a long curved chute, and it leaves ink to spare if the water splashes wide.
2. Let gravity do the placing: Your line falls when you release it. Draw it slightly above where you want it to land and let it settle, rather than drawing exactly on the spot and watching it drop through a gap.
3. Watch the water before you draw: The tap runs for a few seconds after the level starts. Let the first stream fall and see where it lands; the answer is often a small line that redirects it rather than a big one that catches it.

Key features

• Physics you can draw: Every stroke becomes a rigid object that falls, tips and props things up, so the same level has many valid answers.
• A three-star ink limit: Clearing a level is easy; clearing it under the red mark on the ink bar is the actual puzzle.
• 688 classic levels and three more modes: Ramps, seesaws and upturned glasses arrive one mechanic at a time; Don't Spill, Flippy Glass and Precise unlock as you progress.

Game info

• Title: Happy Glass
• Developer: Lion Studios
• Category: Drawing and Physics
• Platform: Web browser (HTML5)
• Levels: 688 in Classic, plus three unlockable modes

Pro tip: The line you draw is a physical object with weight. On levels where the glass is on its side, do not try to funnel water into it — draw a short heavy line on the raised edge of the glass so it tips upright, then a second thin line to catch the stream. Two small strokes often cost less ink than one long one.

Frequently asked questions