Geometry Board
Construct, drag and measure figures.
For checking your work after you’ve tried it yourself.
Step 1: Build
Build
Pick a tool and tap the board. Each new piece remembers what it was built from.
Step 2: Drag
Drag
Move a free point. Everything built from it follows.
Step 3: Check
Check
Say what you think is true and test it across hundreds of positions.
What it does.
Builds ruler-and-compass figures that keep their rules when you drag them, measures lengths and angles (exactly where it can), and tests claims across hundreds of positions.
When it helps.
While trying a problem it'll help to draw an accurate figure, to see whether something you noticed is always true, or to practise the construction itself.
What it won’t do.
It won't prove anything, find relationships for you, or tell you why something is true. Passing a test is evidence, not a proof.
Example.
Draw triangle ABC, add the circumcentre O, the centroid G and the orthocentre H, then check whether O, G and H are collinear.
Select and move: Moves points and the view, and picks objects to style. Drag a free point to move it, or drag empty space to move the view. Tap an object to select it.