This is a great collection of mechanisms. Each reaction is in and of itself a quiz to test the user's knowledge of each mechanistic step in the provided named reactions. Reactions range from simple, elementary mechanisms, to more difficult reactions. Each mechanistic entry can be checked for correctness and, if incorrect, the system will provide helpful hints to assist the user in deducing the correct mechaniam.
The drawing system appears to be a touch finicky. The user must click in exactly the right places on the bonds and atoms to get a system response.