The symbol is most likely the first-angle projection or third-angle projection icon used on engineering drawings. It tells you how the 2D views are arranged relative to the 3D object, and the “angled flag” shape is the standard projection symbol.

What it means

  • In third-angle projection , each view is placed on the same side as the direction you are looking from.
  • In first-angle projection , the views are arranged on the opposite side.
  • The icon helps readers interpret front, top, and side views correctly without confusion.

Why it looks “upside down”

The symbol can seem upside down or reversed because its shape is meant to distinguish the projection method, not to look like a literal flag. The orientation of the cone and circle in the symbol is what matters for identifying the convention.

How to read it

  • If you see this symbol near the title block, check whether it indicates first-angle or third-angle projection.
  • Use that convention to place the views in the correct mental layout before measuring or interpreting features.
  • If the drawing also uses GD&T, this symbol is separate from tolerance symbols and only affects view arrangement.

Common confusion

People sometimes mix this up with:

  • A flag note marker, which points to a specific note on the drawing.
  • Other GD&T symbols, which control tolerances rather than projection.

If you want, I can also show the difference between first-angle and third- angle with a simple sketch.