Add examples. Add more info to README

examples/simple-counter/simple_counter.sv

@@ -0,0 +1,37 @@
+`timescale 1ps/1ps
+`default_nettype none
+
+module simple_counter #(parameter COUNT = 16,
+                        localparam WIDTH = $clog2(COUNT-1)) // <-- ERROR
+    (input wire clock,
+     input wire reset,
+
+     input wire i_inc,
+     input wire i_dec,
+
+     output reg [WIDTH-1:0] o_count);
+
+    logic [WIDTH-1:0] count_next;
+
+    always_comb
+      case ({i_inc, i_dec})
+        2'b01:
+          if (o_count == '0)
+            count_next = WIDTH'(COUNT-1);
+          else
+            count_next = o_count - 1'b1;
+
+        2'b10:
+          if (o_count == WIDTH'(COUNT-1))
+            count_next = '0;
+          else
+            count_next = o_count + 1'b1;
+
+        default: count_next = o_count;
+      endcase
+
+    always_ff @(posedge clock)
+      if (reset) o_count <= '0;
+      else       o_count <= count_next;
+
+endmodule // simple_counter