each color is not necessary. You can 
still get some benefit from using one brush for dark colors, another for light. 
Or one for warm colors, another for cool. Either way, you reduce the risk of 
creating muddy colors by inadvertently mixing very unrelated colors together.</p>
<p>Brushes come in different shapes, materials, and sizes. The common shapes 
are:</p>
<ul>
  <li>Round - an elongated cone</li>
  <li>Flat - rectangular when seen straight on, thin from the side</li>
  <li>Filbert - like a 