
Create a 6-to-1 multiplexer. When sel is between 0 and 5, choose the
corresponding data input. Otherwise, output 0. The data inputs and
outputs are all 4 bits wide.

module TopModule (
  input [2:0] sel,
  input [3:0] data0,
  input [3:0] data1,
  input [3:0] data2,
  input [3:0] data3,
  input [3:0] data4,
  input [3:0] data5,
  output reg [3:0] out
);

