How to play Cubecast: rules and the crossing trick
Everything you need to play Cubecast, plus tips to get a better score.
How to play
- Build a cube model that casts the three shadows of the day, using as few cubes as possible.
- Tap or click a square of the plan to add a cube on it. To remove one, right-click it on a computer, or press and hold it on a phone. Stacks go up to the size of the board.
- Front shadow: imagine a light at the bottom edge of the plan. On the wall behind the model it shows, for each column, the height of its tallest stack: the numbers under the plan.
- Side shadow: now the light is at the left edge of the plan. On the other wall it shows, for each row, the height of its tallest stack: the numbers left of the plan.
- Top shadow: the building seen from above, which squares have at least one cube. Build only on the plain squares of the plan, never on the striped ones.
- Your shadows update live. Next to each number on the plan: ✓ (green) when that column or row matches, ↑ (red) when it is still too low, ↓ (red) when it is too tall.
- The three cards (Front, Side, Top) compare the target shadow with yours square by square: filled = right, dashed = still missing, red and crossed = one too many. A card shows ✓ when its whole shadow matches and ✗ until then. A cube on a striped square turns red.
- Removing cubes is free: press and hold (or right-click) a square to take one cube off, or use the bin to empty the selected square (the last one you touched) in one go.
- Par is the fewest cubes possible. Match par for ⭐⭐⭐, par + 1 or + 2 for ⭐⭐, anything more for ⭐.
- The counter shows cubes used / par. When all three shadows match at par, the game ends by itself. If they match with more cubes, a Finish button appears: stop there, or keep removing cubes to reach par.
- Boards grow during the week: 3×3 on Monday and Tuesday, 4×4 from Wednesday to Friday and 5×5 at the weekend, with a higher par each day. Stacks can be as tall as the board is wide.
- Undo (↶, or Z) and start over (⟲) are free. The 3D model is just for looking: swipe it, use ⟳ or the ← → keys to turn it. With a keyboard, on a focused square: Enter or + adds a cube, − or Backspace removes one, 0 empties it.
- In the settings (⚙) you can turn off the wooden block sound and the vibration. The "?" button opens a legend of everything on the board, and lets you replay the tutorial.
Strategy: the crossing trick
A stack only needs to be tall if it is the one that makes a column or a row reach its shadow. Every other square can hold a single cube. So the question is never "how tall can this be?" but "which stacks really need to be tall?"
Take a 2×2 plan where every square is built and both the front and the side shadows are 2 high: Front Side Top ⬛⬛ ⬛⬛ ⬛⬛ ⬛⬛ ⬛⬛ ⬛⬛
Filling every square to 2 works, but costs 8 cubes: 2️⃣2️⃣ 2️⃣2️⃣
Put the two tall stacks on a diagonal instead. The top-left stack is the tallest of column 1 and of row 1 at the same time; the bottom-right one serves column 2 and row 2. That is the crossing: one stack, two shadows. 6 cubes, which is par: 2️⃣1️⃣ 1️⃣2️⃣
To find crossings, look for a column and a row with the same shadow height whose meeting square is in the top view. Pair up as many as you can, starting with the tallest; each pair saves a whole stack.
More tips: a square's height can never be more than the smaller of its column and row shadows; build the top view first with single cubes, then raise only the stacks that are missing; and when a column's shadow is taller than every row that crosses it on the plan, no crossing is possible there.