10 REM FAST PI CALCULATION
15 X0=SQR(2):Y1=SQR(X0):P0=2+X0
20 A=SQR(X0):X=0
25 X1=(A+1/A)/2
30 A=SQR(X1):B=Y1+1
35 Y2=(Y1*A+1/A)/B
40 P1=P0*(X1+1)/B
45 X=X+1:PRINTX"="P1
50 X0=X1:Y1=Y2:P0=P1:GOTO25