{
  "description": "One-cell circle with a pi rotation; H1 over integers is Z/2 + Z/2 + Z.",
  "B": [[-2,0,0],[0,-2,0],[0,0,0]],
  "C": [],
  "W": [[1,0,0],[0,1,0],[0,0,1]],
  "a": ["1/3","1/4","7/5"],
  "target": "integral"
}