Is my Matrix Arrowhead?
Javascript (ES6), 48 47 bytes

Saved 1 byte thanks to edc65

m=&gt;m.some((r,y)=&gt;r.some((c,x)=&gt;(x*y&amp;&amp;x!=y)^!c))


Returns false for arrowhead matrices and true for non-arrowhead matrices (allowed since any two distinct values can be used to represent true and false)

Test cases:



f=m=&gt;m.some((r,y)=&gt;r.some((c,x)=&gt;(x*y&amp;&amp;x!=y)^!c))
console.log(f([[1, 1, 1], [1, 1, 0], [1, 0, 1]]))
console.log(f([[1, 2, 3, 4], [1, 1, 0, 0], [1, 0, 1, 0], [1, 0, 0, 1]]))
console.log(f([[1, 2, 2, 2], [2, 1, 0, 0], [3, 0, 1, 0], [4, 0, 0, 1]]))
console.log(f([[34, 11, 35, 5], [56, 567, 0, 0], [58, 0, 679, 0], [40, 0, 0, 7]]))
console.log(f([[3, 5, 6], [7, 1, 0], [8, 0, 0]]))
console.log(f([[9, 9, 9, 9], [9, 9, 0, 0], [9, 7, 9, 0], [9, 0, 0, 9]]))
console.log(f([[1, 0, 3, 4], [1, 1, 0, 0], [1, 0, 1, 0], [1, 0, 0, 1]]))
console.log(f([[1, 6, 3, 4], [13, 2, 0, 6], [29, 0, 1, 0], [2, 0, 0, 4]]))