This screenshot provides an overview of Partition Exchange Loading. To the left is a rectangle named as Source. To the right are four rectangles, ordered from top to bottom: Target_P1, Target_P2, Target_P3, and Target_P4. To the right of these is an arrow, with the label Exchange Identities, pointing from left to right. To the right of the arrow is a rectangle named Target_P3. To the right of TARGET_P3 are four rectangles, ordered from top to bottom: Target_P1, Target_P2, Source, and Target_P4.