new pattern

import turtle as t
t.tracer(20)
t.bgcolor('black')
t.setup(1537,865)
t.width(10)
color=('red','blue','green','gold')
for i in range(3040):
      t.pencolor(color[i%4])
      t.fillcolor('black')
      t.begin_fill()
      t.fd(i)
      t.rt(90)
      t.fd(i)
      t.circle(i,90)
      t.fd(i)
      t.rt(270)
      t.bk(i)
      t.lt(90)
      t.fd(i)
      t.lt(90.1)
      t.end_fill()
t.done()