test another example of member.scm Chap11 p3 L6
add two-in-a-row Chap11 p4 L5
modify two-in-a-rwo Chap11 p5 L1
modify two-in-a-row Chap11 p6 L1
add two-in-a-row-b Chap11 p7 L1
modify two-in-a-row Chap11 p7 L5
add sum-of-prefixes Chap11 p9 L5
add sum-of-prefixes-b Chap11 p10 L6
modify sum-of-prefixes Chap11 p11 L5
remind pick Chap11 p13 L5
add scramble-b Chap11 p14 L6
add scramble Chap11 p14 L6