A training desk. Not for sale yet.

Enlightened

Five moves, two passes, and a place to build the argument yourself. The page checks the drills. A hint counts as assisted. The clock is off until you turn it on, and it never fails you.

The drills are original, except one public-domain paragraph from Casaubon, which the drill credits. The neighbouring book is the Rebus series Introduction to Philosophy, Logic volume, CC BY 4.0. Series page. This page does not quote it.