def escapes(cr, ci, it)
    """
    Does iterating z <- z^2 + c escape after it iterations?
    """
    zr = 0.0
    zi = 0.0
    for i in 0...it
        # z <- z^2 + c
        zr,zi = zr*zr - zi*zi + cr, 2*zr*zi + ci
        if zr*zr + zi*zi > 4
            return true
        end
    end
    return false
end

def toChar(p)
    if p
        return " "
    else
        return "X"
    end
end

def mandel(xmin,xmax,xstep, ymin,ymax,ystep, iterations)
  for yc in 1...ystep
      y = yc*(ymax-ymin)/ystep + ymin
      row = Array.new
      for xc in 0...xstep
          x = xc*(xmax-xmin)/xstep + xmin
          row.push escapes(x, y, iterations)
      end
      puts row.collect{|c| toChar(c)}.join
  end
end

mandel(-2.0, 1.0, ARGV[0].to_i, -1.0, 1.0, ARGV[1].to_i, ARGV[2].to_i)