Handy little snippet for generating block shadows with SASS.

block-shadow.sass

=vendor($property, $value)
	-webkit-#{$property}: $value
	-moz-#{$property}: $value
	-o-#{$property}: $value
	#{$property}: $value


=block-shadow($distance, $horizontal, $vertical, $color)
	$property: null
	$i: 1

	@while $i <= $distance
		
		@if $horizontal == left and $vertical == bottom
			$property: $property , -#{$i}px #{$i}px $color

		@else if $horizontal == left and $vertical == top
			$property: $property , -#{$i}px -#{$i}px $color

		@else if $horizontal == right and $vertical == bottom
			$property: $property , #{$i}px #{$i}px $color

		@else if $horizontal == right and $vertical == top
			$property: $property , #{$i}px -#{$i}px $color
		
		$i: $i + 1

	+vendor(box-shadow, $property)

.box
	+block-shadow(5px, left, bottom, #ddd)

box-shadow.css

.box {
	-webkit-box-shadow: -1px 1px #dddddd, -2px 2px #dddddd, -3px 3px #dddddd, -4px 4px #dddddd, -5px 5px #dddddd;
	-moz-box-shadow: -1px 1px #dddddd, -2px 2px #dddddd, -3px 3px #dddddd, -4px 4px #dddddd, -5px 5px #dddddd;
	-o-box-shadow: -1px 1px #dddddd, -2px 2px #dddddd, -3px 3px #dddddd, -4px 4px #dddddd, -5px 5px #dddddd;
	box-shadow: -1px 1px #dddddd, -2px 2px #dddddd, -3px 3px #dddddd, -4px 4px #dddddd, -5px 5px #dddddd;
}

Just updated this to fix a bug where the first shadow is always using the left bottom direction. The output remains unchanged as the bug didn't effect this use case.

Changed three of the if statements to else if statements for better performance.