I need to find the parametric equations of this function or any similar to it, after hours trying with FooPlot i've found this two similar graphs,

x=((63/40)*sin(7s)sin(s))-((9/40)*cos(7s)cos(s))
y=((-63/40)*cos(s)sin(7s))-((9/40)*cos(7s)sin(s))
and
x=3/2*cos(s)+3/2cos(s-s*1/4)
y=3/2*sin(s)-3/2sin(s-s*1/4)

but I cannot get the peaks like the one in the picture, i would be very helpful if you give me some hint, thanks