Activate the helicopter cockpit code multiple times by pressing [R2, L2, R2, L2, R2, L2, R1, L1, R1, L1, R1, L1] seven times, followed by R2, L2, R2, L2, R2, L2(2), R1, L2, R1, L2, R1, L2, R1. A trail of golden nuggets will appear on the road. Collect these nuggets as you move around the city to increase your city fund.