Revision b6956e69-5e6d-41da-9d5e-79fca46a31a6 - Stack Overflow

## Ruby, 82 ##

 e=r=gets.to_f
 (e%2>0&&puts(('*'*(1|2*(r*r-e*e)**0.5)).center r+r)
 e-=1)while e>=-r