A CodePen by Chris Coyier.

Circle-Expando-Buttons.markdown

Circle Expando Buttons

Saw some button where you hover over them and they get kinda painted (http://www.legworkstudio.com/). This isn't quite that, but easier.

A Pen by Chris Coyier on CodePen.

License.

index.html

<a href="#0" class="button"><span>Button</span></a>

<a href="#0" class="button"><span>Button</span></a>

<a href="#0" class="button"><span>Button</span></a>

<a href="#0" class="button"><span>Button</span></a>

<a href="#0" class="button"><span>Button</span></a>

style.scss

@import "compass";
body {
  text-align: center;
  background: #444;
  padding: 1rem;
}

.button {
  background: yellow;
  display: inline-block;
  padding: 2rem 4rem;
  margin: 1rem;
  text-decoration: none;
  font: bold 1rem Sans-Serif;
  color: black;
  position: relative;
  overflow: hidden;
  @include transition(0.7s);
  &:before {
    content: "";
    position: absolute;
    bottom: -40px;
    right: -40px;
    width: 10px;
    height: 10px;
    background: #222;
    border-radius: 50%;
    @include transition(0.7s);
  }
  span {
    position: relative;
  }
  &:hover, &:focus {
    color: white;
    &:before {
      width: 270px;
      height: 270px;
      opacity: 1;
    }
  }
}

.button:nth-child(1) { 
  background: #9b59b6;
}
.button:nth-child(2) { 
  background: #3498db;
  &:before {
    bottom: auto;
    top: -40px;
  }
}
.button:nth-child(3) { 
  background: #e74c3c;
  &:before {
    right: auto;
    left: -40px;
  }
}
.button:nth-child(4) { 
  background: #f1c40f;
  &:before {
    right: auto;
    bottom: auto;
    left: -40px;
    top: -40px;
  }
}
.button:nth-child(5) { 
  background: #1abc9c;
  &:before {
    right: auto;
    bottom: auto;
    left: 90px;
    top: -40px;
  }
  &:hover, &:focus {
    &:before {
      left: -50px;
    }
  }
}