diff --git a/code/bsd_tetris_add_reverse_rotate.patch b/code/bsd_tetris_add_reverse_rotate.patch
deleted file mode 100644
index 95b4e30..0000000
--- a/code/bsd_tetris_add_reverse_rotate.patch
+++ /dev/null
@@ -1,81 +0,0 @@
-diff --git a/tetris.c b/tetris.c
-index 59b6173..84352f5 100644
---- a/tetris.c
-+++ b/tetris.c
-@@ -53,7 +53,7 @@
- #include "screen.h"
- #include "tetris.h"
- 
--#define NUMKEYS 6
-+#define NUMKEYS 7
- 
- cell	board[B_SIZE];
- int	Rows, Cols;
-@@ -170,7 +170,7 @@ main(int argc, char *argv[])
- 	if (pledge("stdio rpath wpath cpath tty unveil", NULL) == -1)
- 		err(1, "pledge");
- 
--	keys = "jkl pq";
-+	keys = "hjkl pq";
- 
- 	classic = showpreview = 0;
- 	while ((ch = getopt(argc, argv, "ck:l:ps")) != -1)
-@@ -226,9 +226,9 @@ main(int argc, char *argv[])
- 	}
- 
- 	snprintf(key_msg, sizeof key_msg,
--"%s - left   %s - rotate   %s - right   %s - drop   %s - pause   %s - quit",
-+"%s - left   %s - ccw  %s - cw   %s - right   %s - drop   %s - pause   %s - quit",
- 		key_write[0], key_write[1], key_write[2], key_write[3],
--		key_write[4], key_write[5]);
-+		key_write[4], key_write[5], key_write[6]);
- 
- 	(void)signal(SIGINT, onintr);
- 	scr_init();
-@@ -286,11 +286,11 @@ main(int argc, char *argv[])
- 		/*
- 		 * Handle command keys.
- 		 */
--		if (c == keys[5]) {
-+		if (c == keys[6]) {
- 			/* quit */
- 			break;
- 		}
--		if (c == keys[4]) {
-+		if (c == keys[5]) {
- 			static char msg[] =
- 			    "paused - press RETURN to continue";
- 
-@@ -313,21 +313,28 @@ main(int argc, char *argv[])
- 			continue;
- 		}
- 		if (c == keys[1]) {
--			/* turn */
--			const struct shape *new = &shapes[
--			    classic? curshape->rotc : curshape->rot];
-+			/* turn ccw */
-+			const struct shape *new = &shapes[curshape->rot];
- 
- 			if (fits_in(new, pos))
- 				curshape = new;
- 			continue;
- 		}
- 		if (c == keys[2]) {
-+			/* turn cw */
-+			const struct shape *new = &shapes[curshape->rotc];
-+
-+			if (fits_in(new, pos))
-+				curshape = new;
-+			continue;
-+		}
-+		if (c == keys[3]) {
- 			/* move right */
- 			if (fits_in(curshape, pos + 1))
- 				pos++;
- 			continue;
- 		}
--		if (c == keys[3]) {
-+		if (c == keys[4]) {
- 			/* move to bottom */
- 			while (fits_in(curshape, pos + B_COLS)) {
- 				pos += B_COLS;
diff --git a/org/cheatsheet.org b/org/cheatsheet.org
index 58d8961..b60a320 100644
--- a/org/cheatsheet.org
+++ b/org/cheatsheet.org
@@ -62,16 +62,17 @@ https://orgmode.org/worg/dev/org-export-reference.html
 *Bold* /italic/ _underline_ +strikethrough+ ~code~ =verbatim=
 
 ** normal
-| key     | usage               |
-|---------+---------------------|
-| M-%     | 替换                |
-| M-;     | 区域切换注释        |
-| C-x C-; | 行切换注释          |
-| C-y     | paste to minibuffer |
-| M-&/!   | async/shell command |
-| C-M-\   | indent-region       |
-| M-y     | past previous       |
-| C-x ^   | enlarge-window      |
+| key       | usage               |
+|-----------+---------------------|
+| M-%       | 替换                |
+| M-;       | 区域切换注释        |
+| C-x C-;   | 行切换注释          |
+| C-y       | paste to minibuffer |
+| M-&/!     | async/shell command |
+| C-M-\     | indent-region       |
+| M-y       | past previous       |
+| C-x ^     | enlarge-window      |
+| C-q <tab> | insert a tab        |
 
 https://www.masteringemacs.org/article/fun-games-in-emacs
 
diff --git a/org/internet_collections.org b/org/internet_collections.org
index 254b67e..9f1faf9 100644
--- a/org/internet_collections.org
+++ b/org/internet_collections.org
@@ -361,6 +361,7 @@ inspiration: Veritasium
 *** [[https://youtu.be/nfF91Z6fqGk][CMD 登录B站]]
 *** [[https://youtu.be/crnEygp4C6g][Jeff Geerling: FINALLY! A GPU works on the Raspberry Pi!]]
 *** [[https://youtu.be/jlPaby7suOc][Every Clojure Talk Ever]]
+*** [[https://youtu.be/CnbVCNIh1NA][Fructure: A Structured Editing Engine in Racket]]
 *** [[https://youtu.be/Fq9chEBQMFE][what if I try to malloc too much memory]]
 *** [[https://youtu.be/zJ-8DZhzBEE][what your favourite pl says about you]]
 *** [[https://youtu.be/9vXKvku6y5A][ArcaOS: Modern OS/2]]
@@ -481,6 +482,7 @@ Huwawei NB!
 ** [[https://marc.info/?l=openbsd-tech&m=167374666324119&w=2][openbsd-tech: xonly on amd64: testing wanted]]
 ** [[https://lists.freebsd.org/pipermail/freebsd-current/2003-July/006889.html][freebsd : Annoucning DragonFly BSD!]]
 ** [[https://minnie.tuhs.org/pipermail/tuhs/2022-April/025643.html][TUHS: Sad News - we last two wonderful people in the past few weeks]]
+** [[https://lore.kernel.org/lkml/63efd7ab.170a0220.3442b.6609@mx.google.com/][Linus: If you cannot explain a merge, then JUST DON'T DO IT]]
 
 * Other
 :PROPERTIES:
diff --git a/org/whatif_openbsd.org b/org/whatif_openbsd.org
index 3e76180..805f8d3 100644
--- a/org/whatif_openbsd.org
+++ b/org/whatif_openbsd.org
@@ -285,7 +285,7 @@ iwx0 at pci0 dev 20 function 3 "Intel Wi-Fi 6 AX201" rev 0x20, msix
 
 ** [[./bbs_gbk_utf8.org][支线任务: 中文 BBS GBK 转 UTF8]]
 
-** @@html:<a href=https://dongdigua.github.io/code/bsd_tetris_add_reverse_rotate.patch type=text/plain>add reverse rotation to BSD Tetris</a>@@
+** [[https://github.com/dongdigua/tetris-custom][Add some useful feature in BSD Tetris]]
 :PROPERTIES:
 :CUSTOM_ID: tetris
 :END: