At the end of the episode, Sheldon tries to perform his own magic trick for Howard using a radioactive isotope—which, in classic Sheldon fashion, is wildly dangerous and unnecessary. Memorable Quote:

The relationship between Leonard and Priya (Raj’s sister) hits a snag when Priya expresses discomfort with Leonard’s close friendship with Penny.

Howard performs a simple card trick for the group, and it drives Sheldon into a frenzy. Despite his high IQ, Sheldon cannot figure out how Howard is doing it.

Sheldon struggles with the idea that something can be "simple" yet beyond his immediate understanding. The Subplot: Priya and Leonard

[s4e18] The Prestidigitation Approximation -

The relationship between Leonard and Priya (Raj’s sister) hits a snag when Priya expresses discomfort with Leonard’s close friendship with Penny. [S4E18] The Prestidigitation Approximation

Howard performs a simple card trick for the group, and it drives Sheldon into a frenzy. Despite his high IQ, Sheldon cannot figure out how Howard is doing it. At the end of the episode, Sheldon tries

Sheldon struggles with the idea that something can be "simple" yet beyond his immediate understanding. The Subplot: Priya and Leonard At the end of the episode