--- a/julia/arrays.jl	Tue Feb 28 13:43:46 2023 +0100
+++ b/julia/arrays.jl	Tue Feb 28 15:17:55 2023 +0100
@@ -352,3 +352,21 @@
     end
     max_encountered
 end
+
+"""Fisher-Yates"""
+function shuffle(a::AbstractVector)
+    for i = length(a):-1:1
+        ix = rand(UInt) % i
+        a[i], a[ix+1] = a[ix+1], a[i]
+    end
+end
+
+function visualizeshuffle(n, m)
+    base = 1:n
+    mat = zeros(Int, n, m)
+    for i = 1:m
+        mat[:,i] .= collect(base)
+        shuffle(@view mat[:,i])
+    end
+    mat
+end