Apparently, Desmos supports using Points as inputs and outputs of functions
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Expression 17: "a" Subscript, "d" "d" , Baseline left parenthesis, "a" , "b" , right parenthesis equals left parenthesis, "a" . "x" plus "b" . "x" , "a" . "y" plus "b" . "y" , right parenthesisadda,b=a.x+b.x,a.y+b.y
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Expression 18: "m" Subscript, "u" "l" "t" "i" , Baseline left parenthesis, "a" , "b" , right parenthesis equals left parenthesis, "a" . "x" times "b" . "x" minus "a" . "y" times "b" . "y" , "a" . "x" times "b" . "y" plus "a" . "y" times "b" . "x" , right parenthesismultia,b=a.x·b.x−a.y·b.y,a.x·b.y+a.y·b.x
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Expression 19: "m" Subscript, "o" "d" "u" "l" "u" "s" , Baseline left parenthesis, "v" , right parenthesis equals StartRoot, "v" . "x" squared plus "v" . "y" squared , EndRootmodulusv=v.x2+v.y2