diff --git a/examples/constants.md b/examples/constants.md
index dca9dc0..ebec261 100644
--- a/examples/constants.md
+++ b/examples/constants.md
@@ -1,6 +1,7 @@
 ```python
 >>> from polyomino.constant import *
 >>> from polyomino.piece import display
+
 ```
 
 ```python
@@ -10,6 +11,7 @@
 +-+ +-+
   | |
   +-+
+
 ```
 
 ```python
@@ -21,6 +23,7 @@
   + +
   | |
   +-+
+
 ```
 
 ```python
@@ -30,6 +33,7 @@
 +   +
 |   |
 +-+-+
+
 ```
 
 ```python
@@ -37,6 +41,7 @@
 +-+-+-+-+
 |       |
 +-+-+-+-+
+
 ```
 
 ```python
@@ -46,6 +51,7 @@
 +-+ +-+
   |   |
   +-+-+
+
 ```
 
 ```python
@@ -57,6 +63,7 @@
 + +
 | |
 +-+
+
 ```
 
 ```python
@@ -66,4 +73,5 @@
 +-+ +-+
 |   |
 +-+-+
+
 ```
\ No newline at end of file
diff --git a/examples/easy.md b/examples/easy.md
index ad53124..663483a 100644
--- a/examples/easy.md
+++ b/examples/easy.md
@@ -17,4 +17,5 @@
 + +-+ +-+
 | |     |
 +-+-+-+-+
+
 ```
\ No newline at end of file
diff --git a/examples/fluid.md b/examples/fluid.md
index c434a9c..75cbb99 100644
--- a/examples/fluid.md
+++ b/examples/fluid.md
@@ -4,24 +4,29 @@
 >>> from polyomino.board import Chessboard
 >>> from polyomino.constant import MONOMINO, DOMINO
 >>> from polyomino.tileset import many
+
 ```
 
 ```python
 >>> Chessboard()
 <polyomino.board.Chessboard object at ...>
+
 ```
 
 ```python
 >>> Chessboard().tile_with_many(DOMINO)
 <polyomino.problem.TilingProblem object at ...>
+
 ```
 
 ```python
 >>> Chessboard().tile_with_set(many(DOMINO).and_repeated_exactly(2, MONOMINO))
 <polyomino.problem.TilingProblem object at ...>
+
 ```
 
 ```python
 >>> Chessboard().tile_with_set(many(DOMINO).and_repeated_exactly(2, MONOMINO)).with_heuristics()
 <polyomino.problem.TilingProblem object at ...>
+
 ```
\ No newline at end of file
diff --git a/examples/gardner.md b/examples/gardner.md
index 2d95b5b..f8998fa 100644
--- a/examples/gardner.md
+++ b/examples/gardner.md
@@ -7,6 +7,7 @@ These examples are taken from chapter 13 of 'Mathematical Puzzles and Diversions
 >>> from polyomino.constant import ONESIDED_TETROMINOS
 >>> from polyomino.constant import TETROMINOS, ALL_PENTOMINOS
 >>> from polyomino.tileset import many, repeated_exactly, any_number_of
+
 ```
 >[...]  
 >In Chapter 3 (problem 3) we considered a polyomino problem dealing with the placing of dominoes on a mutilated chessboard.
@@ -16,17 +17,20 @@ These examples are taken from chapter 13 of 'Mathematical Puzzles and Diversions
 ```python
 >>> Chessboard().remove((0, 0)).remove((7, 7)).tile_with_many(DOMINO)
 <polyomino.problem.TilingProblem object at ...>
+
 ```
 
 [An impossible tiling will give the solution `None`.]
 
 ```python
 >>> Rectangle(4, 4).remove((0, 0)).remove((3, 3)).tile_with_many(DOMINO).solve()
+
 ```
 
 ```python
 >>> Chessboard().remove((0, 0)).remove((0, 7)).tile_with_many(DOMINO).solve().tiling
 [[(0, 1), (0, 2)], [(0, 3), (0, 4)], [(0, 5), (0, 6)], [(1, 0), (1, 1)], [(1, 2), (1, 3)], [(1, 4), (1, 5)], [(1, 6), (1, 7)], [(2, 0), (2, 1)], [(2, 2), (2, 3)], [(2, 4), (2, 5)], [(2, 6), (2, 7)], [(3, 0), (3, 1)], [(3, 2), (3, 3)], [(3, 4), (3, 5)], [(3, 6), (3, 7)], [(4, 0), (4, 1)], [(4, 2), (4, 3)], [(4, 4), (4, 5)], [(4, 6), (4, 7)], [(5, 0), (5, 1)], [(5, 2), (5, 3)], [(5, 4), (5, 5)], [(5, 6), (5, 7)], [(6, 0), (6, 1)], [(7, 0), (7, 1)], [(6, 2), (6, 3)], [(7, 2), (7, 3)], [(6, 4), (6, 5)], [(7, 4), (7, 5)], [(6, 6), (6, 7)], [(7, 6), (7, 7)]]
+
 ```
 
 ```python
@@ -48,6 +52,7 @@ These examples are taken from chapter 13 of 'Mathematical Puzzles and Diversions
 +-+ + + + + + + +
   | | | | | | | |
   +-+-+-+-+-+-+-+
+
 ```
 
 ```python
@@ -69,6 +74,7 @@ These examples are taken from chapter 13 of 'Mathematical Puzzles and Diversions
 +-+-+-+ + +-+-+-+
 |     | | |     |
 +-+-+-+-+-+-+-+-+
+
 ```
 
 ```python
@@ -90,10 +96,12 @@ These examples are taken from chapter 13 of 'Mathematical Puzzles and Diversions
 +-+-+-+-+-+-+ + +
 |     |     | | |
 +-+-+-+-+-+-+-+-+
+
 ```
 
 ```python
 >>> Chessboard().remove((2, 3)).tile_with_many(STRAIGHT_TROMINO).solve()
+
 ```
 
 ```python
@@ -115,11 +123,13 @@ These examples are taken from chapter 13 of 'Mathematical Puzzles and Diversions
 + +-+ + +-+ + +-+
 |   | |   | |   |
 +-+-+-+-+-+-+-+-+
+
 ```
 
 ```python
 >>> [name for name in ONESIDED_TETROMINOS if Chessboard().tile_with_many(ONESIDED_TETROMINOS[name]).solve() is None]
 ['S', 'Z']
+
 ```
 
 As mentioned on p118, there is an easy argument to show that this is impossible - naive search is computationally intractable.
@@ -127,6 +137,7 @@ As mentioned on p118, there is an easy argument to show that this is impossible
 ```python
 >>> Chessboard().tile_with_set(any_number_of([ONESIDED_TETROMINOS['L'], ONESIDED_TETROMINOS['J']]).and_one(TETROMINOS['Square']))
 <polyomino.problem.TilingProblem object at ...>
+
 ```
 
 ```python
@@ -148,4 +159,5 @@ As mentioned on p118, there is an easy argument to show that this is impossible
 +   +-+ +-+ +-+ +
 |   |     | |   |
 +-+-+-+-+-+-+-+-+
+
 ```
\ No newline at end of file
diff --git a/examples/more.md b/examples/more.md
index 4b70c7d..aa30f08 100644
--- a/examples/more.md
+++ b/examples/more.md
@@ -1,6 +1,7 @@
 ```python
 >>> from polyomino.board import Irregular, Rectangle
 >>> from polyomino.constant import TETROMINOS
+
 ```
 
 ```python
@@ -41,6 +42,7 @@
 + +-+ +-+ +-+ +-+-+ +-+ +
 | |     | |     |     | |
 +-+-+-+-+-+-+-+-+-+-+-+-+
+
 ```
 
 ```python
@@ -102,4 +104,5 @@
 +-+ +-+ +
   | | | |
   +-+ +-+
+
 ```
\ No newline at end of file