(This article was first published on

**Freakonometrics - Tag - R-english**, and kindly contributed to R-bloggers)Just imagine that your kids need some help, to prepare fishes for April 1st, like

Her: “please, Daddy, help us to draw some fishes“

Me: “Sure, Daddy is a champion, actually, I do that everyday at work: drawing fishes – and more generally nice stuff – is exactly Daddy’s job“.

OK, no need to talk neither about Talbot’s curves, ellipse negative pedal curve nor Burleigh’s ovals, unless you don’t want to scare them, e.g.

t=seq(0,2*pi,length=100) b=.8 c=sqrt(1-b^2) x=cos(t)-c*sin(t)^2 y=(1-2*c^2+c*cos(t))*sin(t)/b plot(x,y)

From now on, it is rather simple to draw fishes,

t=seq(0,2*pi,length=100) y=cos(t)-sin(t)^2/sqrt(2) x=cos(t)*sin(t) plot(x,y,type="l",axes=FALSE,xlab="",ylab="") polygon(c(-2,-2,2,2), c(-2,2,2,-2),col="light blue",border=NA) polygon(x,y,col="red",border=NA) axis(1) axis(2) lines(x,y,type="l")

so we can easily get nice fishes,

To

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