Symbol Sigma Metal Sign

About the Sigma design

The top and bottom bars run flat and equal, stopping at blunt square ends on the right, and between them two thick diagonals drive inward to one sharp point, like an arrowhead aimed back at the middle. That point falls well short of the bar ends, and the notch cutting in behind it runs nearly half the width of the sign. On the left the bars stop at short vertical edges, and not one corner in the whole shape is rounded.