Write the prompt around a playable rule
The prompt links a drawing gesture to a physical outcome. A length limit makes trade-offs visible, while the slope guide teaches what the marble needs. Keep drawing and simulation as separate steps so players can inspect their line before testing it. Let the first puzzle accept a range of workable shapes rather than a single ideal bridge.
Original concept prompt: “Make a one-line bridge puzzle. Draw a single continuous line between two cliffs; the line becomes a bridge that must support a rolling marble until it reaches the flag. Show ink length remaining and use a gentle slope guide on the first level. Allow the player to erase and redraw before starting the marble.” This is a recipe for an idea, not a claim that this exact game is already playable.
Play, observe and refine one thing at a time
Draw a flat line, a shallow curve and a steep slope, then release the marble. Check whether the line behaves consistently and whether the length meter updates as you draw. If a bridge collapses unexpectedly, show the contact or support rule. If every shape works, make the next gap wider or add one support point to reason about.
Refine one physical property at a time, such as line stiffness or marble speed. If the player can solve by drawing a solid block, limit ink length or require the marble to remain visible. Add new levels that change a single constraint, and observe whether a player can transfer the lesson from the first bridge.
Do not grade a drawing by subjective neatness if the goal is to make a functional bridge. Explain the success condition and accept more than one shape. A forgiving erase-and-redraw step supports experimentation without removing the puzzle.
Playable reference for this prompt: Dunk. Drag back and release to slingshot a basketball into a hoop that moves every shot; clean swishes stack a flaming combo. Use this example to compare the proposed rules with a game you can try now. For your version, use this check: When should the drawn line become a bridge?
Questions about drawing game prompt
When should the drawn line become a bridge?
Let the player finish drawing before starting the marble. This separates editing from simulation and makes it easier to understand why a particular bridge succeeds.
How do I make the ink limit understandable?
Show the remaining length during drawing and define what happens at zero. Test short strokes and very long gestures, including a release outside the drawing area.