Euclid Lab

Explore the 48 propositions of Book I of Euclid’s Elements through reading, construction and proof practice. Euclid Lab separates proposition reading, straightedge-and-compass work and reasoning so you can focus on one activity at a time. Arrange supplied proof blocks to connect premises to conclusions. Scored exercises use semantic checks of geometric relationships and logical dependencies, not the appearance of a drawing or AI grading. Progressive hints and complete solutions, shown on request, help when you get stuck. I.7 currently offers unscored reading, exploration and notes. Freehand notes are also unscored and are not automatically verified as correct proofs. Foundations and I.1–I.12 are free. I.13–I.24 and I.25–I.48 are separate, one-time in-app purchases. Buying one pack does not unlock the other. No subscription is required. Learning progress and notes are stored locally on your device. Learner profiles are not Apple Accounts, and no Euclid Lab account registration is required. Restore Purchases restores eligible content access; it does not synchronize learning progress.