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diff --git a/challenge-242/bruce-gray/fsharp/ch-1_scary.fsx b/challenge-242/bruce-gray/fsharp/ch-1_scary.fsx
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+++ b/challenge-242/bruce-gray/fsharp/ch-1_scary.fsx
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+// For the Halloween season, a scary Haskell-style point-free solution!
+// To execute from the command line: `dotnet fsi fsharp/ch-1_scary.fsx`
+
+let uncurry   f (x, y) = f x y
+let mapBoth   f (x, y) = f x, f y
+let fwdAndRev f (x, y) = f (x, y) , f (y, x)
+
+let diffs = mapBoth Set.ofList >> uncurry Set.difference >> Set.toList
+let task1 = fwdAndRev diffs
+
+
+// Below this point is test harness and data.
+let mutable test_number = 0
+let is (got: 'a) (expected: 'a) (test_name: string) =
+    test_number <- test_number + 1
+    let ok_msg = if (got = expected) then "ok" else "not ok"
+    printfn $"{ok_msg} {test_number} {test_name}"
+    ()
+
+//type intListPair = list<int> * list<int> // XXX Include? move higher?
+type TestRecord = { input: list<int> * list<int>; expected: list<int> * list<int> }
+let tests: TestRecord list = [
+    { input = ( [1; 2; 3]    , [2; 4; 6]    ); expected = ( [1; 3] , [4; 6] ) };
+    { input = ( [1; 2; 3; 3] , [1; 1; 2; 2] ); expected = ( [3;  ] , [    ] ) };
+]
+for test in tests do
+    let got = task1 test.input
+    is got test.expected "Task1 example"