cement-texture-dark.jpg source=http://www.public-domain-image.com/full-image/textures-and-patterns-public-domain-images-pictures/concrete-texture-public-domain-images-pictures/cement-texture.jpg-royalty-free-stock-image.html license=public domain
close-button.png source=PhET Author=SST
icon-friction-homescreen.png source=PhET Author=Bryce
icon-friction-navbar.png source=PhET Author=Bryce
icon-intro-homescreen.png source=PhET Author=Bryce
icon-intro-navbar.png source=PhET Author=Bryce
icon-playground-homescreen.png source=PhET Author=Bryce
icon-playground-navbar.png source=PhET Author=Bryce
mountains.png source=PhET Author=Noah P
reset_arrow.svg source=PhET
skater.png source=PhET
scissors.png source=Open Clip Art license=PUBLIC DOMAIN notes=Modified from http://www.openclipart.org/detail/32341
scissors-closed.png source=Open Clip Art license=PUBLIC DOMAIN notes=Modified from http://www.openclipart.org/detail/32341
scissors-gray.png source=Open Clip Art license=PUBLIC DOMAIN notes=Modified from http://www.openclipart.org/detail/32341
trash-can-open.png source=Font Awesome notes=modified by SR on 2/6/2014
trash-can-open-gray.png source=Font Awesome notes=modified by SR on 2/6/2014