animationPlay

@function foo-shadow($color, $size, $layers: 1) {
  $transparency: (10 - $layers) * .1;
	$opts: ();
	@for $i from 1 to $layers {
		$opts: append($opts, 0 0 0 ($size * $i) transparentize($color, $transparency + (.1 * $i)), comma);
	}
	@return $opts;
}

$colorGood: lawngreen;
$size: 10px;

.circle {
  background: $colorGood
}

.circle.yay {
  @include animation( blammo .5s )
}

@mixin keyframes(blammo) {
  0%, 100%
    +transform( scale(1) )
    box-shadow: 0 0 0 0 transparent
  10%, 80%
    box-shadow: foo-shadow($colorGood, $size, 1);
  20%, 60%
    box-shadow: foo-shadow($colorGood, $size, 2);
  30%
    +transform( scale(1.05) )
    box-shadow: foo-shadow($colorGood, $size, 3);
}