#2301: Turtle Sandwich Standard Model explain

[A two-by-two grid, with a piece of bread next to the top left cell; a turtle shell next to the bottom left cell; lettuce, cheese, and tomato above the top left cell; and an turtle head enclosed in a circle above the top right cell.]

[Top left cell: an image of a sandwich.]

✔ CONFIRMED

[Top right cell: an image of a shell-less turtle sandwiched between two slices of bread.]

(?)

[Bottom left cell: an image of a turtle shell housing lettuce, cheese, and tomato - the contents of a sandwich.]

(?)

[Bottom right cell: an image of a turtle.]

✔ CONFIRMED

[Caption below the panel]

Our lab is working to detect the two missing pieces of the turtle-sandwich standard model.