diff --git a/day1/solution.rkt b/day1/solution.rkt
index 0b2a53e..84c2547 100644
--- a/day1/solution.rkt
+++ b/day1/solution.rkt
@@ -2,9 +2,10 @@
 
 (provide (all-defined-out))
 
-(require qi)
+(require qi
+         (prefix-in list: racket/list))
 
-(define-flow partn (~>> (-< drop-right drop) (count <)))
+(define-flow partn (~>> (-< drop-right drop) (list:count <)))
 
 (define-flow part1* (partn 1))
 (define-flow part1 (~> file->list part1*))
diff --git a/day10/solution.rkt b/day10/solution.rkt
index 11a906e..4d2dec2 100644
--- a/day10/solution.rkt
+++ b/day10/solution.rkt
@@ -32,16 +32,18 @@
 
 (define checker-scores (hash #\) 3 #\] 57 #\} 1197 #\> 25137))
 
+(define checker (make-checker closers))
+
 (define-flow part1*
   (~> sep
-      (amp (make-checker closers))
+      (amp checker)
       (pass char?)
       (amp (hash-ref checker-scores _))
       +))
 (define-flow part1 (~> file->lines part1*))
 
 (define-flow incomplete?
-  (~> (make-checker closers)
+  (~> checker
       (if (or char? null?) ground _)))
 
 (define complete-scores (hash #\) 1 #\] 2 #\} 3 #\> 4))
diff --git a/day11/solution.rkt b/day11/solution.rkt
index f5afd63..7c19535 100644
--- a/day11/solution.rkt
+++ b/day11/solution.rkt
@@ -81,7 +81,7 @@
 (define (stepN n) (flow (feedback n step)))
 
 (define-flow part1*
-  (~> (stepN 100) 2>))
+  (~> (esc (stepN 100)) 2>))
 (define-flow part1 (~> file->grid part1*))
 
 (define-flow part2*
diff --git a/day13/solution.rkt b/day13/solution.rkt
index 494e22a..b8c07a0 100644
--- a/day13/solution.rkt
+++ b/day13/solution.rkt
@@ -35,11 +35,11 @@
   (match instruction
     [`(x ,n)
       (~> (points)
-          (set-map (flow (~> (-< x y) (update-first n) cons)))
+          (set-map (flow (~> (-< x y) (esc (update-first n)) cons)))
           sep set)]
     [`(y ,n)
       (~> (points)
-          (set-map (flow (~> (-< y x) (update-first n) X cons)))
+          (set-map (flow (~> (-< y x) (esc (update-first n)) X cons)))
           sep set)]))
 
 (define (fold instructions points)
diff --git a/day16/solution.rkt b/day16/solution.rkt
index f321d7f..87a0b83 100644
--- a/day16/solution.rkt
+++ b/day16/solution.rkt
@@ -99,7 +99,7 @@
      (define-values (data offset)
        (for/fold ([data null]
                   [offset (+ 11 1 start)])
-         ([_ (in-range length)])
+         ([_ignore (in-range length)])
          (~>> (offset)
               (decode packet-string)
               (== (cons data) _))))
diff --git a/day20/solution.rkt b/day20/solution.rkt
index d3766e1..aae8275 100644
--- a/day20/solution.rkt
+++ b/day20/solution.rkt
@@ -2,7 +2,8 @@
 
 (provide (all-defined-out))
 
-(require qi)
+(require qi
+         (prefix-in list: racket/list))
 
 (define-flow light? (or (eq? 1) (eq? #\#)))
 (define-flow dark? (or (eq? 0) (eq? #\.)))
@@ -102,7 +103,7 @@
             (sub1 ym) (add1 yM))))
 
 (define-flow count-light
-  (~>> hash-values (count light?)))
+  (~>> hash-values (list:count light?)))
 
 (define (count-light-n n)
   (flow (~>> (enhance-image-n n) 1> (ε display-image count-light))))
diff --git a/day3/solution.rkt b/day3/solution.rkt
index ecc3919..e8dd1b2 100644
--- a/day3/solution.rkt
+++ b/day3/solution.rkt
@@ -62,7 +62,7 @@
 (define-flow (fieldth field) (clos (~> X list-ref)))
 (define (criterion-solver selector rows)
   (define (filterc field criterion rows)
-    (define-flow matches (~> (fieldth field) (= criterion)))
+    (define-flow matches (~> (esc (fieldth field)) (= criterion)))
     (filter matches rows))
   ;; we cannot name this loop, because qi's flow has a loop syntactic form that
   ;; confuses our intent.
diff --git a/day4/solution.rkt b/day4/solution.rkt
index 216df11..13e0923 100644
--- a/day4/solution.rkt
+++ b/day4/solution.rkt
@@ -58,7 +58,7 @@
       (hash-ref n #f)
       (if _
         update-board-board
-        (const b))))
+        (gen b))))
 
 (define (find-first-winner moves boards)
   (let loop ([boards boards]
diff --git a/day5/solution.rkt b/day5/solution.rkt
index 797d782..e261dbd 100644
--- a/day5/solution.rkt
+++ b/day5/solution.rkt
@@ -3,6 +3,7 @@
 (provide (all-defined-out))
 
 (require qi
+         (prefix-in list: racket/list)
          "../common.rkt")
 
 (struct point [x y] #:transparent)
@@ -63,7 +64,7 @@
        collect
        (group-by identity)
        (map length)
-       (count (flow (>= 2)))))
+       (list:count (flow (>= 2)))))
 
 (define-flow part1* (~>> list->segments (filter segment-cardinal?) count-overlaps))
 (define-flow part1 (~> (file->list read-ignore-comma) part1*))
diff --git a/day8/solution.rkt b/day8/solution.rkt
index 1382f72..14e9114 100644
--- a/day8/solution.rkt
+++ b/day8/solution.rkt
@@ -96,7 +96,7 @@
        (remove-duplicates (find-pats-matching-digits pats '(0 6 9))))
      ;; 3
      (match-define-values (`(,six) zero-nine)
-       (partition (flow (~>> (subset? one) not)) zero-six-nine))
+       (partition (flow (not (subset? one _))) zero-six-nine))
      ;; 4
      (define C (set-first (set-subtract one six)))
      ;; 5
diff --git a/day9/solution.rkt b/day9/solution.rkt
index 1a3c212..62b8a07 100644
--- a/day9/solution.rkt
+++ b/day9/solution.rkt
@@ -51,7 +51,7 @@
          (if (and% (not (set-member? seen _))
                    (and (< height _) (not (>= 9))))
            (~> (-< cons (~>> 1> (set-add seen)))
-               (basin-size* grid)
+               (esc (basin-size* grid))
                (== (+ size) _))
            (gen size seen)))))