"coffer illusion" meaning in English

{
  "forms": [
    {
      "form": "coffer illusions",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "coffer illusion (plural coffer illusions)",
      "name": "en-noun"
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
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          "source": "w"
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        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Optical illusions",
          "orig": "en:Optical illusions",
          "parents": [
            "Vision",
            "Senses",
            "Perception",
            "Body",
            "All topics",
            "Fundamental"
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        }
      ],
      "glosses": [
        "An optical illusion in which an arrangement of horizontal and vertical bars of various lengths may be viewed as either a series of rectangles or a series of circles."
      ],
      "id": "en-coffer_illusion-en-noun-HpQKuzd4",
      "links": [
        [
          "optical illusion",
          "optical illusion"
        ],
        [
          "horizontal",
          "horizontal"
        ],
        [
          "vertical",
          "vertical"
        ],
        [
          "bar",
          "bar"
        ],
        [
          "length",
          "length"
        ],
        [
          "rectangle",
          "rectangle"
        ],
        [
          "circle",
          "circle"
        ]
      ]
    }
  ],
  "word": "coffer illusion"
}

{
  "forms": [
    {
      "form": "coffer illusions",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "coffer illusion (plural coffer illusions)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
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        "en:Optical illusions"
      ],
      "glosses": [
        "An optical illusion in which an arrangement of horizontal and vertical bars of various lengths may be viewed as either a series of rectangles or a series of circles."
      ],
      "links": [
        [
          "optical illusion",
          "optical illusion"
        ],
        [
          "horizontal",
          "horizontal"
        ],
        [
          "vertical",
          "vertical"
        ],
        [
          "bar",
          "bar"
        ],
        [
          "length",
          "length"
        ],
        [
          "rectangle",
          "rectangle"
        ],
        [
          "circle",
          "circle"
        ]
      ]
    }
  ],
  "word": "coffer illusion"
}