diff --git a/src/aap/tenth.3 b/src/aap/tenth.4
similarity index 98%
rename from src/aap/tenth.3
rename to src/aap/tenth.4
index 8185536a..0b670f29 100644
--- a/src/aap/tenth.3
+++ b/src/aap/tenth.4
@@ -3,16 +3,23 @@ TITLE TENTH
 EXPUNGE .SWAP,.BEGIN,.END,.ELSE,.I
 
 IFNDEF TS,TS==0
+IFNDEF KA,KA==0
+IFNDEF KS,KS==1
+
+IFN TS+KA+KS-1,.ERR Must assemble for one of TS, KA, or KS.
 
 X=14	; pointer into code/parameter field
 PC=15	; the interpreter's program counter
 PP=16	; parameter stack pointer
 P=17	; return stack pointer
-IFE TS,[
+IFN KS,[
 APR=0
 CTYIN=32
 CTYOUT=33
 ]
+IFN KA,[
+TTY=120
+]
 IFN TS,[
 TYIC==1
 TYOC==2
@@ -30,7 +37,7 @@ WORDBUF: 0 ? .=.+10
 WORDBP: 440700,,WORDBUF+1
 
 START:
-IFE TS,	SETZM	CTYIN
+IFN KS,	SETZM	CTYIN
 IFN TS,[
 	.OPEN	TYIC,[.UAI,,'TTY]
 	 .LOSE
@@ -53,15 +60,20 @@ IFN TS,[
 
 ; print ASCII character in AC 0 - changes AC 0
 PUTCHAR:
-IFE TS,[
+IFN KS,[
 	IORI	0,400		; valid bit
 	MOVEM	0,CTYOUT
 	CONO	APR,12000	; 10000 = set flags, 2000 = interrupt flag
 	SKIPE	CTYOUT		; wait for transmission to complete
 	 JRST	.-1
 ]
+IFN KA,[
+	CONSZ	TTY,20
+	 JRST	.-1
+	DATAO	TTY,0
+]
 IFN TS,	.IOT	TYOC,0
-	CAIE	0,IFE TS,[400\]^J
+	CAIE	0,IFN KS,[400\]^J
 	 POPJ	P,
 	MOVEI	0,^M
 	JRST	PUTCHAR
@@ -121,7 +133,7 @@ PRNTNSP:
 
 ; reads one character into AC 0
 GETCH:
-IFE TS,[
+IFN KS,[
 	CONO	APR,12000	; 10000 = set flags, 2000 = interrupt flag
 	MOVE	0,CTYIN
 	CAIN	0,0
@@ -129,6 +141,11 @@ IFE TS,[
 	SETZM	CTYIN
 	TRZ	0,400
 ]
+IFN KA,[
+	CONSO	TTY,40
+	 JRST	.-1
+	DATAI	TTY,0
+]
 IFN TS,	.IOT	TYIC,0
 	CAIN	0,^M
 	 MOVEI	0,^J