Yamashita started working out episodes on Solty Rei and later Pumpkin Scissors. After stints there, he's been working exclusively for Pierrot on Shippuden and that's where he's stayed up until now.
While working on a ton of episodes throughout Shippuden, some of the best places to get his identifying characteristics is the 6th Opening and ep. 143. You can see swords being shaped like triangles in the Sasuke vs. Itachi fight in the 6th OP, and the fight that's right after opening credits in ep. 143 shows off the square fingers and overall flat way that he likes draw hands--along with the triangle swords making their appearance as well.
He was also the storyboarder, director, animation director and provided some key animation for the 12th ED. It is a nice ED but it's hard to get some of his tics from a slow moving ending like that one. Though, I guess you can tell from this one how he likes to play with character's hair (could I have worded that more awkwardly?).
*spoilers up to ep. 149 of Shippuden ahead*
I just watched ep. 149 of Shippuden. While the overall highlight from an animation perspective might have been Chiyuki Tanaka's solid performance as an Animation Director, Yamashita managed to impress and steal the show again. It's a rather short sequence he worked on-- it's in the second half when Utakata and Naruto meet up with a little girl. They think she's innocent, but she's actually being controlled and sets off a paper bomb. The scene might seem tacky when you're reading it, but the storyboarding and the flashy animation hide any flaws in this set-up.
I'll post some pics to actually show you his work. Please note that everyone of these scenes actually look a lot better in motion since that's how they were supposed to viewed; this is animation of course, not comics. Not to mention that I'm using streaming sites to take these shots and I'm a pedestrian photographer.
Ep. 120 (click to get a bigger view of these pics; flat, square-shaped fingers)
Ep. 143 (triangle swords)
Ep. 143 (flat, squarish way of drawing fingers again)
Ep. 149 (not quite as flat fingers as usual, but the actual animation showcases his tendencies with animating certain characters' hair)
OP 6 (swords leaving a triangular path in its wake--I guess that's another way of describing )
And here's a couple of clips with his actual animation in action. The sense of timing for him is something that I find hard to give an accurate description since I'm such a noob at this. I feel that showing his work and seeing it for yourself is better in any case. However, I do not consider these to be the best way to get a sense of his timing. The scenes I've taken a picture of are better examples when you see them, in my opinion.From ep. 88
Omake from ep. 26 (did everything except the flashbacks, of course; Animation Director is Gorou Sessha, whom I might talk later about his impact on the series):
The omake is notably different from his stuff afterwards, so I believe it's safe to say that he's been developing his stuff bit by bit over the course of this long series.
And that's...all I have to say about that.