Quiver.

Concept

A picture made of arrows. Tap an arrow and it slides out along its own body and flies off the board. If anything is in its way, it smacks into it, bounces back, and you lose a heart. Clear the whole shape.

Rules

1. Each arrow is a bent line of cells with a head. When tapped, the whole arrow travels head-first in the head's direction, snaking through its own cells until it leaves the board.
2. Arrows never pass through each other. If another arrow sits anywhere in the head's line of travel, the move fails and costs a heart.
3. Three hearts per puzzle. Clear every arrow to finish the shape.

3D mode

The same rules on a solid shape built from cubes: sphere, cube, torus, pyramid, octahedron or heart. Arrows can point along any of the six directions. Drag to rotate, pinch or scroll to zoom, tap to fire.

Flat 3D puts flat 2D arrows on the faces of a shape built from cubes: cube, brick, tower, plus, stairs or ziggurat. Each face is a grid. An arrow can bend over an edge onto the next face, which ties all the faces into one puzzle. When tapped, an arrow slides along its path and then flies straight off the shape in the direction it points. Anything in that line blocks it, including arrows on a lower step it would pass over. The generator never aims an arrow into a wall.

Each arrow is colored by the direction it flies (orange tones left and right, blues up and down, greens toward and away from you), so you can read a direction even when you only see an arrow end-on.

Because the shapes are solid, the inner arrows are hidden at first. You clear the outer layer and work inward, rotating to find the arrows that have a clear way out.

How puzzles are generated

1. Pick a shape. A shape function marks which cells of a grid belong to the picture, or which faces of a block shape hold arrows.
2. Build arrows in the order a player could clear them. The generator picks a cell whose way out only crosses cells already used and makes it an arrow's head. Then it grows the body backward through unused cells. It repeats this from the outside in until every cell is used, so the shape is always completely full.
3. Mix the edge directions. At each step, heads that would point straight out of the shape are the last choice. Many edge arrows end up running along the edge or across cleared ground, so you have to work your way in instead of peeling the outside in one sweep.
4. Always solvable. The build order is itself a solution: each arrow's way out is clear once the arrows built before it are gone. The furthest unused cell in any direction always has a clear way out, so the build never gets stuck.
5. Varied lengths and an exact count. Each arrow gets its own length (at least 3 cells: short, medium or a long snake). Bodies bend often, straight runs are kept short, bodies tend to curl around the arrows next to them, and on Flat 3D shapes a body wraps over an edge onto the next face whenever it can. No more than three heads side by side point the same way. Lengths are scaled to the cells left so the total lands on the count you picked. If a few arrows come out short, an arrow absorbs a later one whose head touches its tail, which never breaks solvability. Arrows are never more than twice the usual maximum length, so on rare boards the count can be a few over.
6. Measure difficulty. The game simulates clearing every free arrow at once, round after round. The number of rounds is the puzzle's Depth.

Everything comes from one integer seed, so any puzzle can be shared, replayed, or used as a daily challenge.

Difficulty knobs

Ideas for later

• Special arrows: locked arrows that open after a key arrow leaves, two-headed arrows that pick a side, arrows that rotate a quarter turn each move.
• A daily seed with a shared leaderboard for fewest mistakes and fastest clear.
• Shapes from emoji, pixel art or voxel models, so every level is a recognizable object.
• Combo scoring for clearing arrows in quick succession; star rating from hearts left.
• For huge boards: a minimap, and hearts that scale with arrow count.