diff --git a/README.md b/README.md
index 15df295..ebd3e6c 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,17 @@ logic mostly like https://git.crispypin.cc/CrispyPin/marble
 - option to use 8-bit marbles?
 - blueprint rotation?
 
+# physics
+- find direct bounces (todo consistency)
+- execute direct bounces
+- mark tiles as Claimed, ClaimedIndirect, BlockedIndirect, Blocked
+- direct movements can move to any but Blocked tiles
+- indirect movements can only move to ClaimedIndirect
+- Claimed + ClaimedIndirect = BlockedIndirect
+- ClaimedIndirect + ClaimedIndirect = BlockedIndirect
+- Claimed + Claimed = Blocked
+- BlockedIndirect + Claimed = Claimed
+
 ## file hierarchy
 ```
 - assets/
diff --git a/src/editor.rs b/src/editor.rs
index 81abaab..2120942 100644
--- a/src/editor.rs
+++ b/src/editor.rs
@@ -269,15 +269,7 @@ impl Editor {
 		let max = selection.0.max(selection.1) + (1, 1).into();
 		let width = (max.x - min.x) as usize;
 		let height = (max.y - min.y) as usize;
-		let mut board = Board::new_empty(width, height);
-		for (target_x, x) in (min.x..=max.x).enumerate() {
-			for (target_y, y) in (min.y..=max.y).enumerate() {
-				if let Some(tile) = self.source_board.get(Pos { x, y }) {
-					board.set((target_x, target_y).into(), tile);
-				}
-			}
-		}
-		board
+		self.source_board.get_rect(min, width, height)
 	}
 
 	fn save_blueprint(&mut self, selection: (Pos, Pos)) {
@@ -914,14 +906,7 @@ impl Editor {
 						self.grow_board_and_update_view(
 							&mut (pos + (board.width() - 1, board.height() - 1).into()),
 						);
-						for x in 0..board.width() {
-							for y in 0..board.height() {
-								let p = (x, y).into();
-								if let Some(tile) = board.get(p) {
-									self.source_board.set(p + pos, tile);
-								}
-							}
-						}
+						self.source_board.paste_board(pos, &board);
 					}
 				}
 				return;
@@ -1024,14 +1009,7 @@ impl Editor {
 									self.grow_board_and_update_view(
 										&mut (pos + (board.width() - 1, board.height() - 1).into()),
 									);
-									for x in 0..board.width() {
-										for y in 0..board.height() {
-											let p = (x, y).into();
-											if let Some(tile) = board.get(p) {
-												self.source_board.set(p + pos, tile);
-											}
-										}
-									}
+									self.source_board.paste_board(pos, &board);
 								}
 							}
 						}
diff --git a/src/marble_engine/board.rs b/src/marble_engine/board.rs
index 7a401d3..907e0db 100644
--- a/src/marble_engine/board.rs
+++ b/src/marble_engine/board.rs
@@ -117,7 +117,31 @@ impl Board {
 		}
 	}
 
-	pub fn grow_to_include(&mut self, p: Pos) -> (PosInt,PosInt) {
+	pub fn paste_board(&mut self, pos: Pos, source: &Board) {
+		for x in 0..source.width() {
+			for y in 0..source.height() {
+				let offset = (x, y).into();
+				if let Some(tile) = source.get(offset) {
+					self.set(offset + pos, tile);
+				}
+			}
+		}
+	}
+
+	pub fn get_rect(&self, pos: Pos, width: usize, height: usize) -> Board {
+		let mut out = Board::new_empty(width, height);
+		for x in 0..width {
+			for y in 0..height {
+				let offset = (x, y).into();
+				if let Some(tile) = self.get(offset + pos) {
+					out.set(offset, tile);
+				}
+			}
+		}
+		out
+	}
+
+	pub fn grow_to_include(&mut self, p: Pos) -> (PosInt, PosInt) {
 		let mut offset_x = 0;
 		let mut offset_y = 0;
 		if p.x < 0 {