diff --git a/mux_demux/mux_demux.v b/mux_demux/mux_demux.v
index e196646..be2e53a 100644
--- a/mux_demux/mux_demux.v
+++ b/mux_demux/mux_demux.v
@@ -31,4 +31,95 @@ module demux_1n2 #(parameter N = 8) (
 );
     assign a = sel ? 0 : in;
     assign b = sel ? in : 0;
+endmodule
+
+module mux_4n1 #(parameter N = 8) (
+    input [N-1:0] a,
+    input [N-1:0] b,
+    input [N-1:0] c,
+    input [N-1:0] d,
+    input [1:0] sel,
+    output reg [N-1:0] out
+);
+
+    always @(*) begin
+        case (sel)
+            2'b00: out = a;
+            2'b01: out = b;
+            2'b10: out = c;
+            2'b11: out = d;
+            default: out = a;
+        endcase
+    end
+endmodule
+
+module demux_1n4 #(parameter N = 8) (
+    input [N-1:0] in,
+    input [1:0] sel,
+    output reg [N-1:0] a,
+    output reg [N-1:0] b,
+    output reg [N-1:0] c,
+    output reg [N-1:0] d
+);
+    always @(*) begin
+        a = 0; b = 0; c = 0; d = 0;
+
+        case (sel)
+            2'b00: a = in;
+            2'b01: b = in;
+            2'b10: c = in;
+            2'b11: d = in;
+            default: a = in;
+        endcase
+    end
+endmodule
+
+module mux_8n1 #(parameter N = 8) (
+    input [N-1:0] a,
+    input [N-1:0] b,
+    input [N-1:0] c,
+    input [N-1:0] d,
+    input [N-1:0] e,
+    input [N-1:0] f,
+    input [N-1:0] g,
+    input [N-1:0] h,
+    input [2:0] sel,
+    output reg [N-1:0] out
+);
+
+    always @(*) begin
+        case (sel)
+            3'b000: out = a;
+            3'b001: out = b;
+            3'b010: out = c;
+            3'b011: out = d;
+            3'b100: out = e;
+            3'b101: out = f;
+            3'b110: out = g;
+            3'b111: out = h;
+            default: out = a;
+        endcase
+    end
+endmodule
+
+module mux_Nn1 #(
+    parameter DATA_W = 8, // bits por dato
+    parameter SEL_W = 3   // bits de sel -> 2^SEL_W entradas
+)(
+    input [(1<<SEL_W) * DATA_W - 1 : 0] in,
+    input [SEL_W-1:0] sel,
+    output [DATA_W-1:0] out
+);
+    localparam INPUTS = 1 << SEL_W; // 2^3 = 8
+
+    wire [DATA_W-1:0] data [0:INPUTS-1];
+
+    genvar i;
+    generate
+        for (i=0; i<INPUTS; i = i + 1) begin: unpack
+            assign data[i] = in[i * DATA_W +: DATA_W];
+        end
+    endgenerate
+
+    assign out = data[sel];
 endmodule
\ No newline at end of file
diff --git a/mux_demux/mux_demux_tb.v b/mux_demux/mux_demux_tb.v
new file mode 100644
index 0000000..62e20f4
--- /dev/null
+++ b/mux_demux/mux_demux_tb.v
@@ -0,0 +1,43 @@
+`include "./mux_demux/mux_demux.v"
+
+module mux_demux_tb();
+    reg [7:0] a, b;
+    reg sel;
+
+    wire [7:0] out, _a, _b;
+
+    mux_Nn1 #(.DATA_W(8), .SEL_W(1)) mux (
+        .in({b, a}),
+        .sel(sel),
+        .out(out)
+    );
+
+    demux_1n2 demux (
+        .in(out),
+        .sel(sel),
+        .a(_a),
+        .b(_b)
+    );
+
+    initial begin
+        $dumpfile("./mux_demux/mux_demux.vcd");
+        $dumpvars(0, mux_demux_tb);
+
+        a = 20; b = 5; sel = 0;
+        #1
+        $display("a=%d, b=%d, sel=%b out=%d _a=%d, _b=%d", a, b, sel, out, _a, _b);
+        a = 21; b = 5; sel = 0;
+        #1
+        $display("a=%d, b=%d, sel=%b out=%d _a=%d, _b=%d", a, b, sel, out, _a, _b);
+        a = 22; b = 5; sel = 0;
+        #1
+        $display("a=%d, b=%d, sel=%b out=%d _a=%d, _b=%d", a, b, sel, out, _a, _b);
+        a = 22; b = 5; sel = 1;
+        #1
+        $display("a=%d, b=%d, sel=%b out=%d _a=%d, _b=%d", a, b, sel, out, _a, _b);
+        a = 22; b = 15; sel = 1;
+        #1
+        $display("a=%d, b=%d, sel=%b out=%d _a=%d, _b=%d", a, b, sel, out, _a, _b);
+
+    end
+endmodule
\ No newline at end of file