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Hourglass

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In Hourglass the top half of your phone is a sand funnel. The sand flows through the narrow neck at the hinge into jars below. A conveyor belt brings the jars one by one, and you have to fill each one up to its line. The sand is limited, so every grain counts.

How to play

  1. Put the phone flat open on a table: the sand stops.
  2. As you fold the top half, the sand slides toward the hinge. The steeper the phone, the faster it flows.
  3. The belt brings the jars. Fill each jar up to the line on it.
  4. Don't pour sand into a jar marked with a cross; let it go by empty.

Tips

How is the sand simulated?

The sand moves in a simulation made of small cells: each grain looks at the space below and beside it and falls or slides. That is why it piles up like real sand, jams in the neck and speeds up on a slope. The flow rate depends on the fold angle; the more you fold, the more sand passes through the neck.

What do you need?

Katla games run in the browser; there is nothing to download or install. The games read the phone's fold angle from its motion sensor, so they play best on foldable phones such as the Galaxy Z Fold and Z Flip. On a phone that doesn't fold you can tilt the phone with your wrist instead of moving the top half, and most games can also be played by tapping the screen. Motion sensors only work over a secure connection (https).

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