abstract background black bumps caution coloured design equipment floor grunge health no non non-skid non-slip object occupational outdoor outside pad pads path pathway pattern pavers paving plastic prevent prevention rubber safety shape shiny sidewalk skid slip slipping stone street surface texture traction used walkway Dirt yellow aging backgrounds broken brown built cement concrete cracked dirty effect grey history level material obsolete old process revival ridged rough strip urban view wall weathered white wreck blocks feature slabs steps. circles bubbles children happy party slip and slide water anti-slipping circular metal pavement round textures child garden kidengarden kids laugh play toys collage color colorful colors paper tatters tearing wallpaper