diff --git a/darwin/draw.m b/darwin/draw.m
index 337bd30d..514590f3 100644
--- a/darwin/draw.m
+++ b/darwin/draw.m
@@ -40,7 +40,7 @@ void uiDrawPathNewFigureWithArc(uiDrawPath *p, double xCenter, double yCenter, d
 	sinStart = sin(startAngle);
 	cosStart = cos(startAngle);
 	startx = xCenter + radius * cosStart;
-	starty = yCenter - radius * sinStart;
+	starty = yCenter + radius * sinStart;
 	CGPathMoveToPoint(p->path, NULL, startx, starty);
 	uiDrawPathArcTo(p, xCenter, yCenter, radius, startAngle, sweep);
 }
@@ -61,8 +61,7 @@ void uiDrawPathArcTo(uiDrawPath *p, double xCenter, double yCenter, double radiu
 	CGPathAddRelativeArc(p->path, NULL,
 		xCenter, yCenter,
 		radius,
-		// TODO explain this
-		-startAngle, -sweep);
+		startAngle, sweep);
 }
 
 void uiDrawPathBezierTo(uiDrawPath *p, double c1x, double c1y, double c2x, double c2y, double endX, double endY)
diff --git a/unix/draw.c b/unix/draw.c
index 2bcbce78..001e76b2 100644
--- a/unix/draw.c
+++ b/unix/draw.c
@@ -152,15 +152,12 @@ static void runPath(uiDrawPath *p, cairo_t *cr)
 			cairo_new_sub_path(cr);
 			// fall through
 		case arcTo:
-			// cairo_arc() and cairo_arc_negative() only go clockwise
-			// TODO explain why this works
-			// don't use cairo_arc(); that requires us to put the starting point as the ending point
-			cairo_arc_negative(cr,
+			cairo_arc(cr,
 				piece->d[0],
 				piece->d[1],
 				piece->d[2],
-				-(piece->d[3]),
-				-(piece->d[3] + piece->d[4]));
+				piece->d[3],
+				piece->d[3] + piece->d[4]);
 			break;
 		case lineTo:
 			cairo_line_to(cr, piece->d[0], piece->d[1]);
diff --git a/windows/draw.c b/windows/draw.c
index 9fab786d..a9d41901 100644
--- a/windows/draw.c
+++ b/windows/draw.c
@@ -185,11 +185,11 @@ static void drawArc(uiDrawPath *p, struct arc *a, void (*startFunction)(uiDrawPa
 	sinx = sin(a->startAngle);
 	cosx = cos(a->startAngle);
 	startX = a->xCenter + a->radius * cosx;
-	startY = a->yCenter - a->radius * sinx;
+	startY = a->yCenter + a->radius * sinx;
 	sinx = sin(a->startAngle + a->sweep);
 	cosx = cos(a->startAngle + a->sweep);
 	endX = a->xCenter + a->radius * cosx;
-	endY = a->yCenter - a->radius * sinx;
+	endY = a->yCenter + a->radius * sinx;
 
 	// now do the initial step to get the current point to be the start point
 	// this is either creating a new figure, drawing a line, or (in the case of our full circle code above) doing nothing
@@ -202,7 +202,7 @@ static void drawArc(uiDrawPath *p, struct arc *a, void (*startFunction)(uiDrawPa
 	as.size.width = a->radius;
 	as.size.height = a->radius;
 	as.rotationAngle = 0;		// as above, not relevant for circles
-	as.sweepDirection = D2D1_SWEEP_DIRECTION_COUNTER_CLOCKWISE;
+	as.sweepDirection = D2D1_SWEEP_DIRECTION_CLOCKWISE;
 	if (a->sweep > M_PI)
 		as.arcSize = D2D1_ARC_SIZE_LARGE;
 	else