@testset "Move k backward" begin
    @testset "k=3" begin
        circular = false
        k = 3
        @test squaresub(1, circular, k) == 1
        @test squaresub(2, circular, k) == 1
        @test squaresub(3, circular, k) == 1
        @test squaresub(4, circular, k) == 1
                       
        @test squaresub(11, circular, k) == 1
        @test squaresub(12, circular, k) == 2
        @test squaresub(13, circular, k) == 3
    end
    @testset "k=1" begin
        circular = false
        k = 1
        @test squaresub(1, circular, k) == 1
        @test squaresub(2, circular, k) == 1
        @test squaresub(3, circular, k) == 2
        @test squaresub(4, circular, k) == 3
        
        @test squaresub(11, circular, k) == 3
        @test squaresub(12, circular, k) == 11
        @test squaresub(13, circular, k) == 12
    end
    @testset "k=10" begin
        circular = false
        k = 10
        @test squaresub(1, circular, k) == 1
        @test squaresub(2, circular, k) == 1
        @test squaresub(3, circular, k) == 1
        @test squaresub(4, circular, k) == 1
        
        @test squaresub(11, circular, k) == 1
        @test squaresub(12, circular, k) == 1
        @test squaresub(13, circular, k) == 1
    end
end