PopUp Geometry:The Mathematics behind PopUp Cards 
by Joseph O'Rourke 
I would like to thank Ryuhei Uehara at JAIST, who found several errors as he translated the book to Japanese.
Chap 
Page 
Location 
Old 
New 
Explanation 
Corrector 
Date 

1 
10 
Exercise 1.5 
The equallength cuts are slanted, while the valley creases are vertical. (Otherwise several creases are needed to flatten.)  Ryuhei Uehara 
15Sep2024 

8 
108 
Answer to Exercise 1.5 
a mountain fold halfway between the slanted valley folds, and with the same slant. 
a vertical mountain fold halfwaybetween the vertical valley folds.  Corrected answer to exercise. 
Ryuhei Uehara

15Sep2024 
Chap 
Page 
Location 
Old 
New 
Explanation 
Corrector 
Date 

5 
66 
Figure 5.9 caption 
x to p. p 
x to p. 
Typo 
Ryuhei Uehara 
15Sep2024 
5 
76 
(2) display 
Δ abf Δ acf 
Δ abf, Δ acf 
Typo 
Ryuhei Uehara 
15Sep2024 
5 
77 
Exercise 5.8 
the intersection of a vertical plane through the center b of the sphere Sb

the intersection of the sphere Sb and a vertical plane through the center b of Sb

Typo 
Ryuhei Uehara 
15Sep2024 
6 
92 
enumerated list 
(1), (3), (3) 
(1), (2), (3) 
Typo 
Ryuhei Uehara 
15Sep2024 
6 
94 
line 8 of 6.3.3 
θ = 0 
θ = 0 ° 
Typo 
Ryuhei Uehara 
15Sep2024 
7 
101 
definition of intractable 
"no one knows how to solve large instances" 
"no one knows how to solve large instances efficiently" 
Oversight 
Ryuhei Uehara 
15Sep2024 