Possible Clues:

• Exam given in spots?
• Blot interpretation check?
• Evaluation with inkblots
• This scorechart dismisses one failing personality assessment
• You might see a butterfly during one
• Inkblot technique
• Exam with significance attached to blot out of one's mind?
• Trick cyclist's technique might make Thatcher cross
• Study of ink-blots others scratch out
• Cor, the shrink acts, somehow spilling ink - for this!