Thanks! Here it is then.
When the first lemming in the top-right corner goes right next to the left-side wall, set him to a builder so he makes one step, and then leave these lemmings for the moment. Instead, turn your attention to the one below, and make him build a wall going up to the right wall from his starting point. Then, when he\s finished, start building towards the gap in the brick wall closer to the centre of the level, and make sure you start fairly low down your ladder. Then, when the lemming goes just to the left of the gap, he\ll stop building. Click him when he starts walking left, and repeat this with timing so he goes into the gap, and carry on clicking so he builds up something of a replacement for the wall. Now back to the two lemmings. When one walks onto the step we made earlier, set him as a basher. He\ll bash through the wall, with a line of a one-pixel width just below him. He\ll carry on through your replacement wall without stopping, freeing the builder lemming in the process, and will bash until the end, swiftly avoiding bashing into the iron. Et voila! Three rescued lemmings.
