diff --git a/README.md b/README.md
index 979430d..380e722 100644
--- a/README.md
+++ b/README.md
@@ -234,7 +234,7 @@ tek4010 has the following options:
 	-full		in this mode the tek4010 emulator creates a full screen window, and
 			uses the full resolution of the 4014 with the enhanced graphics module
 			installed, scaled down to the actual window size. Use control-q to
-			close the tek4010 window. This option is experimental.
+			close the tek4010 window.
 
 	-ARDS		display ARDS data			
 
diff --git a/tek4010 b/tek4010
index 3cc78df..168a39e 100755
Binary files a/tek4010 and b/tek4010 differ
diff --git a/tektests/circles.c b/tektests/circles.c
new file mode 100644
index 0000000..415bcc4
--- /dev/null
+++ b/tektests/circles.c
@@ -0,0 +1,74 @@
+#define MAXX 1024
+#define MAXY 680
+
+#include <stdio.h>
+#include <math.h>
+
+int xs,ys;
+
+void startDraw(int x1,int y1)
+{
+    if (x1 < 0) x1 = 0;
+    if (x1 >= MAXX) x1 = MAXX -1;
+    if (y1 < 0) y1 = 0;
+    if (y1 >= MAXY) y1 = MAXY - 1;
+    putchar(29);
+    putchar((y1 >> 5) + 32);
+    putchar((y1 & 31) + 96);
+    putchar((x1 >> 5) + 32);
+    putchar((x1 & 31) + 64);
+    xs = x1;
+    ys = y1;
+}
+
+void draw(int x2,int y2)
+{
+    int hxchange, lychange;
+
+    if (x2 < 0) x2 = 0;
+    if (x2 >= MAXX) x2 = MAXX -1;
+    if (y2 < 0) y2 = 0;
+    if (y2 >= MAXY) y2 = MAXY - 1;
+
+    if ((y2 >> 5) != (ys >> 5))        /* if high y has changed */
+	putchar((y2 >> 5) + 32);
+    hxchange = (x2 >> 5) != (xs >> 5);
+    lychange = (y2 & 31) != (ys & 31);
+    if (hxchange || lychange) putchar((y2 & 31) + 96);
+    if (hxchange)                                     /* if high order x has changed */
+    	putchar((x2 >> 5) + 32);
+    putchar((x2 & 31) + 64);
+    xs = x2;
+    ys = y2;
+}
+
+void endDraw()
+{
+    putchar(31);
+    fflush(stdout);
+}
+
+int drawCircle(int x,int y,int r)
+{
+	int i;
+	double arg;
+    	startDraw(x + r, y);
+    	for (i = 0; i <= r; i++) {
+        	arg = (double)(i) * 6.283185307 / (double) r;
+		draw(x + (int)((double)r * cos(arg)), y + (int)((double)r * sin(arg)));
+    	}
+    	endDraw();
+}
+
+int main (int argc, char *argv[])
+{
+	drawCircle(512, 340, 200);
+        drawCircle(612, 340, 100);
+        drawCircle(412, 340, 100);
+        drawCircle(512, 240, 100);
+	drawCircle(512, 440, 100);
+	startDraw(212,340); draw(812,340); endDraw();
+	startDraw(512,040); draw(512,640); endDraw();
+
+	startDraw(1,1); endDraw(); // move the cursor out of the way
+}
diff --git a/tektests/circles.plt b/tektests/circles.plt
new file mode 100644
index 0000000..4b4412b
--- /dev/null
+++ b/tektests/circles.plt
@@ -0,0 +1 @@
+*t6HHzG+`GfGmFsEyDC,eAk@q5^w\}Y-cWiTnRtOyLH.dEiAn4^sZxV|Q/aMeHjDn3_rZuUyP|K0`Ec@f2ZhUkOmIpCr1]tWuQwKxEy0_zY{RLF|@{/ZTNzGyAx.[wUuOtIrCp-]mWkQhKfFc@`,[/|UyPuKrFnAj+\eXaS.|OxJsFnBi*_d[-XyTtQnNiLcI,}GwDqBk@e)_+]y\s[mZfY`Y*zYtXnYhYbY){Zu[o\i]c_(}*@wBqDkGeI'LzNtQoTiXd[&_z+BuFpJlOgScX%~\z,AvFsKoPlUh[e-@bF`K$}Q{Wx]v.CtIsOqUp[o/AnGmNTZl0@mFLRnYo_p1EqKsQtWv]x2C{I}O%`UbZe3@hElKoPsUvZz_~4D&cHgMlQpVuZz^5A'dEiHoLtOzRT(eWkYq\w^}6@)cAiCoDuE{F*bGhGnGtH*t6HHzG+`GfFlDrCx@~5^,d[iXnTsQxL|H-aCd4^hYkTnNpHsBt3\vVwPJxDw2^XvRtLsFp@n1ZkThOdJaE,|@x0\sWnTiPdM+~JxHrElDfB`A*zAt@nAhAbB)|DvEpHjJdM(PzTuWp\l1@gEdJ`O'}TzZx2@uFtLrRqX^p3DqJPrVt\u4BxHzN}T(`Yd^g5ClHpLuQzTX)d[j^p6@vC|D*bFhGnGtH*t0@@z/_+`_f^l\r[xX~V,dSiPnLsIxD|@-a.[dVhQkLnFp@s-ZtTvNwHBx,\wVPvJtDs+^pXnRkLhGdBa*],|XxTsOnLiHdE+~Bx@r)]l\fZ`Y*zYtXnYhYbZ)|\v]p*@jBdE(HzLuOpTlXg]d+B`G'}LzRxXu^t,DrJqPVp\q-BHrNtTuZx.@zF}L(`QdVg[l/@pDuIzLP)dSjVpXv[|\*b^h_n_t0@'p3DDvC|C(bBh@n2_t\zZ)`WeTjPoMtHxD}1_*`ZdUgPjJlDo0^pXrRsLFt@s/ZTrNpHoBl.\jVgPdK`F)}Ax-\tXoSjPeL`I(zFtDnAh@b,^'|]v]p\j]d]&~^x-@rAlDfF`I%{LvPqSlXh\c.A`F$|KyPvVt\q/BpHnNmTZl0@mFLnRpXq^t1DvJyP|U%`Zc_h2DlHqMvP{T&`WfZl\r_x3@~B'dCjCpD-x3DD~C.dCjBp@v2_|\/bZhWmTrPwM|H0`De1_hZlUoPrJtDw0^xXzR{LF|@{/ZTzNxHwBt.\rVoPlKhFeA`-\/|XwSrPmLhIbF.|DvAp@j,^d]-~]x\r]l]f^`-@,zAtDnFhIcL+~PyStXp\k.AhFdKaP*~V|\y/BxHvNuTZt0@uFLvRxXy^|1D~J+aPdUhZk_p2DtHyM~P,cThWnZt\z_-`3@fBlCrCxD*t&Tt9L!`0@4@ a A
\ No newline at end of file
diff --git a/tektests/incremental.c b/tektests/incremental.c
index bef8ab8..92cfc99 100644
--- a/tektests/incremental.c
+++ b/tektests/incremental.c
@@ -21,7 +21,7 @@ void startDraw(int x1,int y1)
     ys = y1;
 }
 
-extern void endDraw()
+void endDraw()
 {
     putchar(31);
     fflush(stdout);
diff --git a/tektests/makefile b/tektests/makefile
new file mode 100644
index 0000000..60a0b64
--- /dev/null
+++ b/tektests/makefile
@@ -0,0 +1,7 @@
+all: incremental circles
+
+incremental: incremental.c
+	gcc -o incremental incremental.c -lm
+
+circles: circles.c
+	gcc -o circles circles.c -lm