6. Count the number of triangles in the figure.



Translate the above text into English, please keep the original text's line breaks and format, and output the translation result directly.
【Analysis】There are $(6+5+4+3+2+1) \times 2=42$ triangles with one additional line, which adds 12 more, and two additional lines add 24 more.
Two lines together also add one more, so in total there are $42+24+1=67$ triangles.