Geometrical frustration is a simple yet profound concept in condensed matter physics that can give rise to exotic quantum matters like spin liquid. In this talk, I will propose a new source of geometrical frustration from the orbitals instead of the spins of the electrons. A concrete platform for realizing such orbital geometrical frustration is the twisted bilayer graphene (TBG) at fractional filling, where we can map the configurations of electrons to the tiling patterns of trimers. From this mapping, we discover novel charge fractionalization behavior. Furthermore, we find an emergent exact global symmetry, dubbed ``tile-invariant symmetry”. Quantum fluctuation would generate spontaneous breaking of the tile-invariant symmetry, giving rise to an exotic, gapless Mott insulator.