As in -- extremely sharp.
Have you ever seen right angles on the corners of DNA bands in agarose? See for yourself. Click the figure at right to enlarge.
2% agarose horizontal gels. All pictures on this page are from otherwise routine 5 mm-thick 10 cm-long fresh-poured submarine minigels. No molded plastic cases. No pre-casts. No cooling system. Just a slab gel in a reservoir with two electrodes. 100 bp band at bottom.