Pistons

Pistons are solid blocks that extend from the floor or the ceiling and pull back. One moment the way is clear, the next it's blocked. Just like Gates, on piston stages the moment you release the ball is part of the solution.

How pistons move

Each piston runs its own cycle, extending from zero to full length and retracting again. The motion is a smooth wave: the piston lingers a little at fully extended and fully retracted and moves faster in between. Pistons on the same stage can have different cycle lengths and start times.

Pistons are solid: a ball that hits one bounces off it like a wall or the floor. You can't draw anywhere the piston can reach, meaning the space it fills at full extension plus a 5-centimetre margin.

Pistons are introduced around the middle of Level 2. Drifting meteors in space stages work in a similar way: they move back and forth between two points and timing matters.

Getting past a piston

Under it (a piston from the ceiling)

A piston coming down from the ceiling squeezes the height the ball can pass through. Either the piston is retracted when the ball arrives, or the ball's flight stays below its tip. A low, fast shot spends less time under the piston.

Over it (a piston from the floor)

A piston rising from the floor blocks the path. Either it's short when the ball goes by, or the ball flies higher than its full length. A flight that clears the full length takes timing out of the equation entirely; it usually costs more ink but is safer.

Timing

1. Measure how long the ball takes to reach the piston. At the same power it's identical every time, because the physics engine is deterministic.
2. Watch the piston's cycle and release so that the way is open when the ball gets there.
3. If it fails, change only the release moment, not the drawing. Keeping drawing and power fixed shows you which change actually helped.

More in this section

• SpikesTouch them and the ball pops and the stage restarts. Your margin is a few centimetres.
• PitsA ball that falls in is lost. Jump it, or cross it at speed.
• PipesTakes a slow ball from the floor and drops it from the ceiling. Speed is everything.
• GatesSlides up and down in front of the hole. When you shoot matters as much as what you draw.
• Wall behind the ballThe target is behind you. Send the ball forward, then bring it back.
• TrianglesTheir slope carries the ball upward. Used well, a free ramp.
• No-draw zonesYou can't draw in the hatched area. The solution has to live outside it.
• Rubber blocksBounces the ball without losing speed. Think of it as a spring you can't move.
• Magnetic floorsSlows a touching ball by 18 m/s every second. Cross fast or don't touch it.
• Sticky floorsThe ball sticks and the shot ends. Your drawings stay, though.
• Ceiling targetThe hole is in the ceiling, not the wall. You have to send the ball up through it.
• Black holesPulls in a passing ball and swallows one that gets too close. A slingshot at the right distance.