Euclid Lab vs HDLSim

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.

HDLSim is a digital electronics lab on your iPhone. Write Verilog, compile it for the EPM240 CPLD and watch it run on a virtual development board, with a 2D schematic and a 3D breadboard. WHAT YOU CAN DO • Verilog editor with compilation and error messages. • EPM240 CPLD simulator: load your design and test its inputs and outputs on the board. • 2D schematic: place components, wire them and simulate the circuit. • Boolean equation compiler: truth table, Karnaugh map, minimum form and a gate circuit built with chips. • Step-by-step guided lessons. • 3D bench and breadboard: the same circuit built in 3D, with wires, resistors, LEDs and more. • Guided labs: Ohm's law, dividers, diodes and rectifiers, transistors, op-amps, logic gates, adder, latch, 555 timer and 7-segment display. • Your projects are stored on your iPhone. PLANS • Free: Verilog editor, CPLD simulator, 2D schematic and 3D bench, designs and labs with up to 7 breadboard components on the 170, 400 or 830-point board the circuit needs, and boolean equations of up to 4 inputs and 1 output (the circuit it builds does not count toward the 7-component limit while unedited). Includes ads. • Pro: everything in Free with no ads, designs with more than 7 components, every lab in the catalog and equations of up to 6 inputs and 6 outputs. Pro is an auto-renewing subscription, monthly or yearly, at the price shown in the app. Payment is charged to your Apple ID when you confirm the purchase. The subscription renews automatically unless you cancel it at least 24 hours before the end of the current period. Manage or cancel it in Settings > your name > Subscriptions. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy: https://hdlsim.web.app/privacy.html