r=480;c.width=r*4;λ=0;for(φ=a=Math.PI/2;φ>-a;φ-=1/r){λ+=a;x.lineTo(C(φ)*S(λ-t)*r+2*r,(C(t=t+1/r)*S(φ)+S(t)*C(φ)*C(λ-t))*r+r)}x.stroke()

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