multiple absorbers or targets you'll see multiple spikes because we know the speed of sound in tissue we can convert this time of arrival into depth so this time trace is essentially a one dimensional image we call that a scan right or 1d image if we scan the system across the Tish we got a 2d image you would call that be Skinner right now if you're Astros game on a tissue surface you got a 3d image so that's the basic concept and this is the detail now maybe I should skip this is this photograph shows the first 3d