diff --git a/3/main.scm b/3/main.scm
index 259a23d..5eba1bb 100644
--- a/3/main.scm
+++ b/3/main.scm
@@ -1,5 +1,6 @@
 (import (scheme base)
         (scheme char)
+        (scheme cxr)
         (scheme file)
         (scheme process-context)
         (scheme write))
diff --git a/4/GNUmakefile b/4/GNUmakefile
deleted file mode 100644
index eed98a1..0000000
--- a/4/GNUmakefile
+++ /dev/null
@@ -1,2 +0,0 @@
-# -*- makefile-gmake -*-
-include ../gnu.mk
diff --git a/4/main.scm b/4/main.scm
deleted file mode 100644
index 3779750..0000000
--- a/4/main.scm
+++ /dev/null
@@ -1,116 +0,0 @@
-(import (scheme base)
-        (scheme cxr)
-        (scheme file)
-        (scheme process-context)
-        (scheme write))
-
-(define (pad item lst)
-  (cons item (reverse (cons item (reverse lst)))))
-
-(define (make-list len fill)
-  (let loop ((len len)
-             (acc '()))
-    (if (zero? len)
-        acc
-        (loop (- len 1) (cons fill acc)))))
-
-(define (get-cell lol row col)
-  (list-ref (list-ref lol row) col))
-
-(define (get-reachables table wid hgh)
-  (let loop ((row 1)
-             (col 1)
-             (sum 0))
-    (if (> row hgh)
-        sum
-        (if (> col wid)
-            (loop (+ row 1) 0 sum)
-            (begin
-              (let ((cell (get-cell table row col)))
-                (if (zero? cell)
-                    (loop row (+ col 1) sum)
-                    (let ((nbors (+ (get-cell table (- row 1) (- col 1))
-                                    (get-cell table (- row 1) col)
-                                    (get-cell table (- row 1) (+ col 1))
-                                    (get-cell table row (- col 1))
-                                    (get-cell table row (+ col 1))
-                                    (get-cell table (+ row 1) (- col 1))
-                                    (get-cell table (+ row 1) col)
-                                    (get-cell table (+ row 1) (+ col 1)))))
-                      (if (< nbors 4)
-                          (begin
-                            (loop row (+ col 1) (+ sum 1)))
-                          (loop row (+ col 1) sum))))))))))
-
-(define (get-reachables/mark-for-deletion table wid hgh)
-  (let loop ((row 1)
-             (col 1)
-             (sum 0)
-             (newtbl '())
-             (newcurrow '()))
-    (if (> row hgh)
-        (values sum (pad (make-list (+ wid 2) 0) (reverse (map (lambda (row) (pad 0 row)) newtbl))))
-        (if (> col wid)
-            (loop (+ row 1) 1 sum (cons (reverse newcurrow) newtbl) '())
-            (begin
-              (let ((cell (get-cell table row col)))
-                (if (zero? cell)
-                    (loop row (+ col 1) sum newtbl (cons cell newcurrow))
-                    (let ((nbors (+ (get-cell table (- row 1) (- col 1))
-                                    (get-cell table (- row 1) col)
-                                    (get-cell table (- row 1) (+ col 1))
-                                    (get-cell table row (- col 1))
-                                    (get-cell table row (+ col 1))
-                                    (get-cell table (+ row 1) (- col 1))
-                                    (get-cell table (+ row 1) col)
-                                    (get-cell table (+ row 1) (+ col 1)))))
-                      (if (< nbors 4)
-                          (loop row (+ col 1) (+ sum 1) newtbl (cons 0 newcurrow))
-                          (loop row (+ col 1) sum newtbl (cons 1 newcurrow)))))))))))
-
-(define (part1 file)
-  (with-input-from-file file
-    (lambda ()
-      (let* ((char->one-or-zero (lambda (char) (if (char=? char #\@) 1 0)))
-             (lines (let loop ((lines '()))
-                      (let ((line (read-line)))
-                        (if (eof-object? line)
-                            (reverse lines)
-                            (loop (cons line lines))))))
-             (padded-lines (map (lambda (line)
-                                  (pad 0 (map char->one-or-zero (string->list line))))
-                                lines))
-             (len (length (car padded-lines)))
-             (wid (- len 2))
-             (hgh (length padded-lines))
-             (table (pad (make-list len 0) padded-lines)))
-        (display (number->string (get-reachables table wid hgh)))
-        (newline)))))
-
-(define (part2 file)
-  (with-input-from-file file
-    (lambda ()
-      (let* ((char->one-or-zero (lambda (char) (if (char=? char #\@) 1 0)))
-             (lines (let loop ((lines '()))
-                      (let ((line (read-line)))
-                        (if (eof-object? line)
-                            (reverse lines)
-                            (loop (cons line lines))))))
-             (padded-lines (map (lambda (line)
-                                  (pad 0 (map char->one-or-zero (string->list line))))
-                                lines))
-             (len (length (car padded-lines)))
-             (wid (- len 2))
-             (hgh (length padded-lines))
-             (table (pad (make-list len 0) padded-lines)))
-        (let loop ((tbl table)
-                   (sum 0))
-          (let-values (((removed newtbl) (get-reachables/mark-for-deletion tbl wid hgh)))
-            (if (zero? removed)
-                (begin
-                  (display sum)
-                  (newline))
-                (loop newtbl (+ removed sum)))))))))
-
-(for-each part1 (cdr (command-line)))
-(for-each part2 (cdr (command-line)))
diff --git a/4/makefile b/4/makefile
deleted file mode 100644
index 058141b..0000000
--- a/4/makefile
+++ /dev/null
@@ -1,2 +0,0 @@
-# -*- makefile-bsdmake -*-
-.include "../common.mk"