Blue diamond shape (lozenge / rhombus).
<div style="display:inline-block;padding:0 3px;background-color:#BDC"><a href="//commons.wikimedia.org/wiki/File:Blue_diamond.png" title="File:Blue diamond.png"><b>Original: </b></a></div> <div style="display:inline-block;padding:3px 0;"><a href="//commons.wikimedia.org/wiki/User:Paracel63" title="User:Paracel63">Per A.J. Andersson</a></div> <div style="display:inline-block;padding:0 3px;background-color:#CCF">Vector: </div> <div style="display:inline-block;"><a href="//commons.wikimedia.org/wiki/User:OmegaFallon" title="User:OmegaFallon">OmegaFallon</a></div>
<span class="int-own-work" lang="en">Own work</span>; vectorization of: <a href="//commons.wikimedia.org/wiki/File:Blue_diamond.png" title="File:Blue diamond.png">Blue diamond.png</a>