Doodle Road

Draw a road the ball will actually follow

The moment you lift your finger, gravity takes over: the ball drops onto whatever you have drawn and rolls along it. So the trick is to draw with physics in mind, not just to connect the ball to the flag. Gentle downhill slopes keep it moving; a line that is too flat lets it stall, and a wall that is too steep bounces it back or flips it off. Think about momentum: build a little downhill run before any gap you need the ball to clear.

The gray ledges scattered around each level are fixed and solid. Use them. A short stroke that bridges two ledges, or a curved lip that catches a falling ball and redirects it, is usually cleaner than one long line dragged across the whole screen.

Ink is the real puzzle

You do not get unlimited ink, and the meter is what turns this from doodling into a puzzle. Every stroke eats into it, so the elegant solution is usually the short one. The upside: you can keep drawing while the ball is already rolling, which lets you react. Patch a gap just before the ball reaches it, or nudge its path at the last second.

• Favour short, well-placed strokes over long sweeping ones to save ink for later in the level.
• Draw slopes running downhill in the direction you want the ball to travel, and keep them shallow enough to build speed without launching it.
• If a run fails, the level resets with a full ink refill, so treat each attempt as a scouting trip that teaches you where the ball really wants to go.
• Detour through the stars only when it costs little; they are your score across all twelve levels, but reaching the flag comes first.

Three strokes worth practising

Most levels fall to one of three shapes. The bridge is a short, slightly downhill line connecting two gray ledges; keep it shallow so the ball crosses without gaining wild speed. The catch-cup is a small curve drawn under a falling ball, a shallow U with its lip on the far side; it soaks up the fall and sends the ball back out in the direction you want. The launch ramp is a downhill run that flattens right at its end, built just before a gap; the ball gathers speed on the slope and hops the hole in one clean flight.

Here is how they combine. Say the ball starts on a high ledge on the left, the flag sits low on the right, and a star floats over a pit in the middle. Draw a catch-cup just below the ledge's edge, facing right. Release, and the ball drops in, swings through the curve, and rolls out with all that falling speed banked. One short bridge carries it to the next ledge, a small ramp fires it through the star and over the pit, and it rolls down to the flag. Four short strokes, most of the meter untouched, and gravity did the heavy work. If the cup spits the ball out too fast and it overshoots your bridge, redraw it wider and shallower on the next attempt. A rounder curve keeps more speed, a tighter one kills it.

Where draw-a-line games came from

Drawing lines for physics to play with is one of the internet's favourite game ideas. Line Rider, made in 2006 by a Slovenian art student named Bostjan Cadez, let you sketch slopes for a tiny sledder and became a web sensation; people still build elaborate tracks timed to music. Crayon Physics Deluxe, by Finnish developer Petri Purho, won the grand prize at the 2008 Independent Games Festival with the same core trick: whatever you draw becomes a solid object and obeys gravity.

Doodle Road turns that free-form toy into a proper puzzle by rationing the ink. Line Rider hands you an infinite pen and asks for creativity. This game hands you a meter and asks for judgement: twelve hand-built levels, each a small argument about where a line is truly needed and where falling will do the job for free. Since the stars are your score across the whole set, the long game is finishing each level with strokes to spare, then spending the surplus on a star detour when the road happens to pass close.