REM Will Bolam 2000
REM bifurcation diagram
REM k horizontal, x vertically

SCREEN 12
CLS
FOR K = 2.9 TO 4 STEP .001
        x0 = .5
        FOR I = 1 TO 500
                x0 = K * x0 * (1 - x0)
        NEXT
        FOR I = 1 TO 100
                x0 = K * x0 * (1 - x0)
                LINE ((K - 2.9) / 1.1 * 640, x0 * 480)-((K - 2.9) / 1.1 * 640, x0 * 480)
        NEXT
NEXT
INPUT A