gistfile1.txt

message Point {
  required int32 x = 1;
  required int32 y = 2;
  optional string label = 3;
}
 
message Line {
  required Point start = 1;
  required Point end = 2;
  optional string label = 3;
}
 
message Polyline {
  repeated Point point = 1;
  optional string label = 2;
}