flowchart TB
    access[Access site]
    activation[Activation]
    valid[Valid key?]
    remaining[Activations remaining?]
    checkout[Stripe Checkout]
    questionnaire[Questionnaire]
    activate[Activate key]
    results[Show table of results]
    error[Error]
    physical[Ordered physical copy?]
    receive[Receive physical copy in mail]
    done[Done]

    access-->activation
    activation-->checkout
    checkout-->activation
    activation-->valid
    valid--"No"-->error
    valid--"Yes"-->remaining
    remaining--"Yes"-->questionnaire
    remaining--"No"-->results
    error-->activation
    questionnaire-->activate
    activate-->results
    results-->physical
    physical--"No"-->done
    physical--"Yes"-->receive
    receive-->done