Some very specific obsessions recur throughout his ludography: themes involving the subconscious, the nature of the mind, and the manipulated hero.

[H]e went home […] and told them about his trip; how at Ripon he saw the gassiest man he had ever seen; an old steamboat captain by the name of Mapes; how I told him where we were going to have colleges, mills, stores, etc., […] the last time I saw him before he died he told me that he had seen all my gassy story carried out, and more too.

You are leaving tonight? — Even so.

A parabolic conoid is a paraboloid; an elliptic conoid is an ellipsoid.