General discussion, page-7362

The guys are talking about the "wall" or volume of shares for sale at 40c. Approximately 1.2m at that point during the day. It represents a wall of resistance as there is a lot of selling pressure relative to other price points throughout the day. It should have taken a while to chew through the entire 1.2m shares on offer at 40c but instead a buyer came through and bought them all in one hit aka lined wiped.

You can see the walls by looking at the "depth" of bids at any given time. You can also see them reflected in hindsight by looking at the chart.