diff --git a/fuzzers/013-clbncy0/top.py b/fuzzers/013-clbncy0/top.py
index 174385c3..531372c1 100644
--- a/fuzzers/013-clbncy0/top.py
+++ b/fuzzers/013-clbncy0/top.py
@@ -2,33 +2,16 @@ import random
 random.seed(0)
 import os
 import re
-
-
-def slice_xy():
-    '''Return (X1, X2), (Y1, Y2) from XRAY_ROI, exclusive end (for xrange)'''
-    # SLICE_X12Y100:SLICE_X27Y149
-    # Note XRAY_ROI_GRID_* is something else
-    m = re.match(
-        r'SLICE_X([0-9]*)Y([0-9]*):SLICE_X([0-9]*)Y([0-9]*)',
-        os.getenv('XRAY_ROI'))
-    ms = [int(m.group(i + 1)) for i in range(4)]
-    return ((ms[0], ms[2] + 1), (ms[1], ms[3] + 1))
-
+from prjxray import util
 
 CLBN = 400
-SLICEX, SLICEY = slice_xy()
-# 800
-SLICEN = (SLICEY[1] - SLICEY[0]) * (SLICEX[1] - SLICEX[0])
-print('//SLICEX: %s' % str(SLICEX))
-print('//SLICEY: %s' % str(SLICEY))
-print('//SLICEN: %s' % str(SLICEN))
 print('//Requested CLBs: %s' % str(CLBN))
 
 
 def gen_slices():
-    for slicey in range(*SLICEY):
-        for slicex in range(*SLICEX):
-            yield "SLICE_X%dY%d" % (slicex, slicey)
+    for _tile_name, site_name, _site_type in util.gen_sites(['SLICEL',
+                                                             'SLICEM']):
+        yield site_name
 
 
 DIN_N = CLBN * 8