54
Somebody had to do it:
library(plotrix)
n <- 28
col <- rainbow(n)
plot(-2:2, -2:2 ,type="n",xlab="",ylab="",main="28 stupid overlapping circles")
for(i in 0:(n-1)){
theta <- i/n * 2 * pi
draw.circle(cos(theta), sin(theta), radius=1, border=col[i],lty=1,lwd=1)
}