Maybe I read it wrong or not enough coffee yet but the router bit will have a bearing for the sides to ride the pattern so you need to take that into account for the width of the arrow shape. Not having done this I'm wondering about the length of the bit and distance from the bearing to the end of the bearing.........brain freeze, use a collar not a bearing and adjust the depth...........it's like coming out of a coma sometimes. Or am I missing this all together?Find the design you want or draw it. Then trace it onto a piece of wood of some sort (MDF, masonite, plywood), then cut it out with a coping or jig saw then use a bit like one of these to route it out. The bit will follow the template exactly so be sure to sand it nice and smooth.
4Pcs Pattern Flush Trim Router Bit Set 1/4 inch Shank Template Router Bits 1/2 inch Cutting Dia Woodworking Router Tool by CHoiKWong (1/2 inch Cutting Diameter, yellow) - - Amazon.com