making sandwich layers and animation delays

layer-animation.less

// ---- assign z-index to layers ----
.layerZIndex(12);

#vegetable {
	.layer-13 { // top bun needs to be behind
		z-index: 0;
	}
	// each layer needs the distance tweaked between the next
	.layer-11 {
		margin-top: -10%;
	}
	.layer-7 {
		margin-top: -4%;
	}
	.layer-6 {
		margin-top: -3%;
	}
	.layer-5 {
		margin-top: -6%;
	}
	.layer-4 {
		margin-top: -7%;
	}
	.layer-3 {
		margin-top: -7%;
	}
	.layer-2 {
		margin-top: -4%;
	}
	.layer-1 {
		margin-top: -10%;
	}
	.layerDelay (13);
}
// ---- CUSTOM MIXINS ----
// ---- make default z-index ----
.layerZIndex (@index) when (@index > 1) {
	.layer-@{index} {
		z-index: @index;
	}
	.layerZIndex(@index - 1);
}
.layerZIndex (0) {}

// ---- create cascading animation delays ----
.layerDelay (@index) when (@index > 0) {
	.falling.layer-@{index} {
		-moz-animation-delay: (.15s * @index);
		-webkit-animation-delay: (.15s * @index);
	}
	.layerDelay(@index - 1);
}
.layerDelay (0) {}