@misc{indiciae1e6cf83bf211,
  title = {Leonardo's constraint: two opaque objects cannot be seen in the same direction.},
  author = {Hiroshi Ono and Linda Lillakas and Philip M Grove and Masahiro Suzuki},
  year = {2003},
  doi = {10.1037/0096-3445.132.2.253},
  url = {https://pubmed.ncbi.nlm.nih.gov/12825639/},
  note = {Source identifier: 12825639}
}