
pi = 3.14159  :  cx=0.4

R{t} = cx + Cos[t] / cx 

X{t} = 4 *R{t} * Cos[t]       ' Conversion from polar to rectangular.
Y{t} = 4 *R{t} * Sin[t]
Z{t} = 0                              ' 2D graph; set 3rd coordinage to zero.
Fa<t> = <X,Y,Z>

t0 =-pi  :  tf = pi + pi/12  :  n = 200
Plot[Fa, {t, t0, tf, n}]

