; To plot this, press Esc, press P twice, then press Enter
[t * (t^2 - 1) / (t^2 + 1), 2 * (t^2 - 1) / (t^2 + 1)]
; A curvilinear diamond
[2 * (COS t)^3, 2 * (SIN t)^3]
; Infinity
[3 sin t, 2 sin (2*t)]
; A pretzel
[(t / pi) * (12 * (t / pi)^2 - 9), (((t / pi)^2 - 1) * 16 * (t / pi)^2 + 2)]
; A fish.  Move the cross to its eye position
[3/2 * COS t * (COS t + 1), 2 * SIN (2*t)]
; An embellished valentine
[SIN (2*t) + SIN t, - COS (2*t) - COS t]
; A spiral
[EXP (t/4) * SIN (2*t), EXP (t/4) * COS (2*t)]
; Twin spirals
[2/3 * t * COS (7/2 * t), 2/3 * t * SIN (7/2 * t)]
; A slinky gone bad
[t - 11/10 * SIN (3*t), - 22/10 * COS (3*t)]
