audio control electronic knob mixer mixing desk music Recording sound studio technology tune alert appropriate-behavior appropriate-behaviour approval approved bush-reserve care communicating communication concern conservation conserve controlled directions dog dogs inform information informing lead leash natural nature observation observe old park permitted pets protect protection public-park rules rust rusty sign signs warning warning-sign white Denmark gate iron light lock metal reflection ripple shadow sluice strong water construction detour do not instruction restriction safety temporary traffic turn canine clean clean-up cleanliness denial denied doggy-do dogs-prohibited droppings exception excrement excreta hygiene mess messy not-allowed not-permitted pickup poo prepared prohibited prohibition regulations responsible sanitation waste access armed authorities authority availability available badges barriers cars deployment equipment flashing-lights law law-&-order lights motor-bikes National-Day on-duty on-the-job order patrols police police-vehicles power presence security Singapore symbols traffic-control uniforms vehicles weapons