diff --git a/battery-case-generator.py b/battery-case-generator.py
index f924526..5841c7b 100755
--- a/battery-case-generator.py
+++ b/battery-case-generator.py
@@ -21,6 +21,7 @@ parser.add_argument('--thickness', default=3.0, type=float, help='Thickness of m
 parser.add_argument('--lid', default=0.2, type=float, help='How much extra play to give the lid')
 parser.add_argument('--tooth', default=0.8, type=float, help='How much to round the edges of the teeth')
 parser.add_argument('--flex-granularity', default=1.8, type=float, help='How much space to give a pair of flex lines')
+parser.add_argument('--plug-play', default=0.3, type=float, help='How much smaller to make the plug than the hole')
 parser.add_argument('--verbose', action='store_true', help='Print computed parameter values')
 args = parser.parse_args()
 assert (args.dimension % 2) == 1
@@ -41,28 +42,36 @@ else:
     args.hole = float(args.hole)
     assert(args.height != None)
 
-args.kerf2         = args.kerf/2
-args.grid          = args.hole+args.padding
-args.radius        = args.hole/2
-args.corner        = args.corner_length*args.thickness
-args.corner_s      = args.corner*args.stretch
-args.corner_radius = 3*args.corner_s/math.pi
-args.plug_radius   = args.corner_radius-args.thickness
-args.corner_inset  = args.corner_s*math.sqrt(3)/math.pi
-args.plug_inset    = args.plug_radius/math.sqrt(3)
-args.interior_edge = args.grid*args.dimension*0.5+args.outside_padding
-args.plug_edge     = args.interior_edge-args.thickness
-args.disc_radius   = 0.45*(math.sqrt(3)-1)*args.plug_edge+args.plug_inset
-args.exterior_edge = args.interior_edge+2.0*args.thickness
-args.interior_leg  = (args.interior_edge-args.horizontal_finger-args.kerf)/2-args.corner_inset
-finger_length      = args.interior_edge-2.0*args.corner_inset
-args.n_hor_fingers = max(int(finger_length/args.horizontal_finger/2), 1)
-args.exterior_leg  = (finger_length-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
-args.wall_leg      = (args.interior_edge-args.corner-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
-args.exterior_slot = (args.interior_edge-args.horizontal_finger+args.kerf)/2
-args.n_ver_fingers = int((args.height+args.extra_height)/args.vertical_finger)
-top_slot           = args.extra_height+args.thickness+0.5*args.height
-args.slots         = [top_slot, top_slot+10.0]
+SUITABLE = False
+while not SUITABLE:
+    args.kerf2         = args.kerf/2
+    args.grid          = args.hole+args.padding
+    args.radius        = args.hole/2
+    args.corner        = args.corner_length*args.thickness
+    args.corner_s      = args.corner*args.stretch
+    args.corner_radius = 3*args.corner_s/math.pi
+    args.plug_radius   = args.corner_radius-args.thickness
+    args.corner_inset  = args.corner_s*math.sqrt(3)/math.pi
+    args.plug_inset    = args.plug_radius/math.sqrt(3)
+    args.interior_edge = args.grid*args.dimension*0.5+args.outside_padding
+    args.opening_edge  = args.interior_edge-args.thickness
+    args.plug_edge     = args.opening_edge-args.plug_play
+    args.disc_radius   = 0.45*(math.sqrt(3)-1)*args.plug_edge+args.plug_inset
+    args.exterior_edge = args.interior_edge+2.0*args.thickness
+    args.interior_leg  = (args.interior_edge-args.horizontal_finger-args.kerf)/2-args.corner_inset
+    finger_length      = args.interior_edge-2.0*args.corner_inset
+    args.n_hor_fingers = max(int(finger_length/args.horizontal_finger/2), 1)
+    args.exterior_leg  = (finger_length-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
+    args.wall_leg      = (args.interior_edge-args.corner-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
+    args.exterior_slot = (args.interior_edge-args.horizontal_finger+args.kerf)/2
+    args.n_ver_fingers = int((args.height+args.extra_height)/args.vertical_finger)
+    top_slot           = args.extra_height+args.thickness+0.5*args.height
+    args.slots         = [top_slot, top_slot+10.0]
+    if args.exterior_leg > 2:
+        SUITABLE=True
+    else:
+        args.outside_padding += .5
+        args.padding         += .2 # Try again with more padding
 
 if args.verbose:
     print(args, file=sys.stderr)
@@ -104,7 +113,9 @@ def draw_plane(cx, cy, layer):
     global HOLES, SHAPES, MARKS
     if layer=='interior':
         edge = args.interior_edge
-    elif layer=='plug' or layer=='plug_mark' or layer=='opening':
+    elif layer=='opening':
+        edge = args.opening_edge
+    elif layer=='plug' or layer=='plug_mark':
         edge = args.plug_edge
     else:
         edge = args.exterior_edge
@@ -131,19 +142,14 @@ def draw_plane(cx, cy, layer):
         turtle.forward(edge-2.0*args.corner_inset)
         turtle.circle(-args.corner_radius, 60)
     elif layer=='plug' or layer=='plug_mark':
-        turtle.forward(args.plug_inset)
         turtle.pendown()
-        for side in range(6):
+        for side in range(3):
+            turtle.forward(0.5*edge)
             turtle.right(90)
-            turtle.circle(0.5*edge-args.plug_inset, 180)
+            turtle.circle(0.5*edge, 120)
             turtle.right(90)
-            turtle.circle(-args.plug_radius, 60)
-    elif layer=='opening':
-        turtle.forward(args.plug_inset)
-        turtle.pendown()
-        for side in range(6):
-            turtle.forward(edge-2.0*args.plug_inset)
-            turtle.circle(-args.plug_radius, 60)
+            turtle.forward(0.5*edge)
+            turtle.right(60)
     else:
         turtle.pendown()
         for side in range(6):