Challenging, beyond recursion practice in

this class, just an exercise to dissect

hybird structure of tuples and lists

Construct the following by ONE

expression

try ::nil style instead of $[]$

Hint: try one at a time, figure out

expressions for $1,2,$dots$9$

val a$1=$ #$1$ L$2$;

val a$2=$ hd$($a$1)$;

val a$3=$ #$1$ a$2$;

val a$4=$ hd a$3$;

to get $1,$ combine the above

val L$2)$