navy check Golden Fleece 3 btn sack suit
light blue check shirt with red windowpane
All from Brooks Brothers
2 checks, a stripe and a dot pattern. Blue in all 4 pieces. Red is an accent in the shirt and dominates in the tie. Yellow is an accent in the tie and dominates the pocket square.
Lots of great stuff in this thread but the Duke of Windsor on page 65 of Dressing the Man is still my favorite 4 pattern combo.