Rule: 1 if ultrasonic_sensor_Value > number then go = 1 and turn = 0 Rule: 2 if ultrasonic_sensor_Value ≤ number then go = 0 and turn += 90 Rule: 3 stop
start :- nxt_ultrasonic_sensor(port,Value), Value > number, nxt_go(1). start :- nxt_ultrasonic_sensor(port,Value), Value =< number, nxt_turn(speed,90). start :- go(0).