# Lieb lattice: a square lattice plus the midpoints of its edges.
# Lines 1-2: lattice vectors a1 and a2 (Cartesian).
# Remaining lines: fractional coordinates of each atom, with an
# optional species label used to name the types in the filter.
1.0  0.0
0.0  1.0
0.0  0.0   corner
0.5  0.0   edge
0.0  0.5   edge