working loop's in LESS

loop.less

@iterations: 30;

	.loopingClass (@iterations);

	// helper class, will never show up in resulting css
	// will be called as long the index is above 0
	.loopingClass (@index) when (@index > 0) {

		~.ico@{index} {
			// your resulting css
			background: url("../img/ico@{index}.png");
		}

		// next iteration
		.loopingClass(@index - 1);
	}

	// end the loop when index is 0
	.loopingClass (0) {}

any demo ?