APL.cs

unsafe class Program
{
    delegate int? bar(int* i);
    static void Main(string[] args)
    {
        int[] ω = {};
        var Ʃ = 42;
        int? Φ = null;
        bar ϼ = default;

        ϼ=Δ=>Φ??=ω[^+Ʃ--..]?[Ʃ**&Δ[ϼ(++Δ-Ʃ)??*Δ]^(δ:Ʃ,β:..^~Φ)!.δ];
        // Exercise for reader: Invoke ϼ so it does not fail
    }
}