Wall behind the ball

On some stages the wall with the hole isn't in front of the ball but behind it. You can only shoot the ball to the right, so you have to send it forward first and then somehow bring it back. These stages appear towards the end of Level 1 and become more common later.

Why it's hard

The ball's path has two halves: out and back. The speed, direction and height on the way back depend on what happened on the way out, so a small difference in power grows on the return. The ball may also start near the middle of the play area, leaving a long way to travel back to the wall.

Three ways to bring it back

1. A steep spring

Draw a near-vertical spring in front of the ball, facing it. The ball hits it and bounces back with most of its speed. The spring's slope sets the return angle: lean it back slightly and the ball comes back rising; keep it upright and it comes back flat. Simple, but sensitive to power.

2. A reverse booster

Draw a booster in front of the ball, right to left. The ball brakes on it, stops and gets thrown to the left. The booster speeds the ball back up over the same distance it took to stop it, so the ball leaves at the speed it arrived with, along the line of the booster. There's none of the angle sensitivity of a spring bounce, which makes it more predictable. Just make the booster long enough to stop the ball: about 17 centimetres for every 1 m/s of speed. The first stage of Level 2 teaches exactly this. See Booster.

3. A head wind

A long wind arrow pointing left across the ball's path slows the ball, stops it and pushes it back. Because the strip keeps acting on the ball, you can shape the return with an arrow angled up or down.

Wall behind plus a gate

Some stages put a gate on the hole behind you. The longer flight makes timing more delicate. A reverse booster is especially useful here because the return path is less affected by small changes in power.

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.
• 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.
• PistonsExtends from the floor or ceiling and pulls back. You get past by choosing your moment.
• 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.