Box Stack — Play Free Online

Free spatial reasoning game — instant play, no signup, no download

Box Stack shows a three-dimensional arrangement of cubes and asks which flat shadow it would cast from above. You are mentally collapsing a solid down to a plan view — the same operation an architect does reading a floor plan, or anyone does working out whether a piece of furniture fits through a door.

How to play

Study the 3D stack of boxes shown.

Work out which cells would be covered looking straight down.

Pick the matching top-down shape from the options.

Correct answers load a taller or more irregular stack.

Your score combines accuracy with how quickly you answered.

What it actually trains

Spatial visualisation — building and manipulating a mental model of a solid object. Unlike mental rotation, nothing turns here; the work is in projecting three dimensions down to two.

Tips to score higher

Height is irrelevant. A column of four cubes casts exactly the same shadow as one cube.

Work column by column, not layer by layer. Ask of each footprint position: is there anything above it?

Trace the outline of the stack with your finger on the screen. Physically following the edge helps more than staring.

Eliminate options by looking for a single cell that is obviously covered or obviously empty.

Frequently asked questions

Does the shadow include cubes hidden behind others?

Yes. Anything occupying a footprint position counts, whether or not you can see it from the drawing's angle.

Is this the same as mental rotation?

No. Mental rotation turns the object; this projects it. People are often good at one and not the other.

Is spatial ability trainable?

Spatial visualisation is one of the better-supported trainable skills, and practice on tasks like this does improve performance on similar tasks.

Any advice for the irregular stacks?

Count the footprint cells first. If your chosen answer has the wrong number of filled cells, it is wrong regardless of shape.