sigmaAllow = 15000 // psi
width = 11 // inch
p = 150 // Force on shelf - lbs
distance = 12 // inches
FOS = 2
thickness = sqrt(distance * p * FOS * 6 / (sigmaAllow * width))
filletR = thickness * 2
shelfMountL = 9
wallMountL = 8

bracket = startSketchAt([0, 0])
  |> line(end = [0, wallMountL])
  |> tangentialArc({ radius = filletR, offset = 90 }, %)
  |> line(end = [-shelfMountL, 0])
  |> line(end = [0, -thickness])
  |> line(end = [shelfMountL, 0])
  |> tangentialArc({
       radius = filletR - thickness,
       offset = -90
     }, %)
  |> line(end = [0, -wallMountL])
  |> close(%)
  |> extrude(length = width)