Crossword puzzle clue "kid's art activity or something seen four times in this puzzle's solution"

Kid's art activity ... or something seen four times in this puzzle's solution?

Something often seen on a street corner, briefly ... or, literally, something seen in each corner of this puzzle

Mark used four times in this puzzle's solution

Feeling that you've seen something before seen something before

Obstacles seen four times in this puzzle's completed grid?

Unforeseen development ... or a feature seen four times in this puzzle's answers?

Mark that appears four times in this puzzle (hint: the baseball player who's the answer to this puzzle uses one, too)

Trellis flower, and something found four times in this puzzle