How many lines are needed to create 6 triangles on W? Basically, the question started with a little argument I had with my friend. My friend said he thinks it's possible to draw only 2 lines on the letter "W" and make 6 triangles, and I played around with it, but I couldn't really do it, so I told him I don't think it's possible, and we need at least 3 lines. 

We kept arguing, but I really couldn't prove that we need more than 2 lines on letter "W" to create 6 triangles except that I couldn't find a way of doing so. 
Is there any proof for this kind of problem?

PS. Sorry. I didn't clarify. You CANNOT combine one or more triangles to form a triangle and count that separately. Triangles must be INTERNALLY disjoint.
For instance, if triangles ABC, BCD can be combined to form triangle ADC, then we don't count ADC as a triangle.
No one said the W couldn't be "cursive"...


Perhaps not what the OP was looking for (and I'm aware this post was brought back from YEARS AGO, but I just thought I'd share this) but this solution does contain $6$ triangles with only $2$ lines
Three parallel lines one at the top, one middle, one bottom, and, if tri inside tri is allowed, you have $6$. Of these, $3$ are true and $3$ more are built around their respective parent.