module block1(clk,a,b,c);
output [3:0] b,c;
input [3:0] a;
input clk;
reg [3:0] b,c;
always @(posedge clk)
  begin
    b=a;
    c=b;
    $display("Blocking:a=%d,b=%d,c=%d.",a,b,c);
    end
endmodule