diff --git a/sky130/klayout/sky130A_mr.drc b/sky130/klayout/sky130A_mr.drc
index e01de04..96fa34e 100755
--- a/sky130/klayout/sky130A_mr.drc
+++ b/sky130/klayout/sky130A_mr.drc
@@ -26,20 +26,34 @@
 backend_flow = AL
 
 # enable / disable rule groups
-if $feol == "0"
-    FEOL    = false # front-end-of-line checks
+if $feol  == "1"        || $feol == "true"
+  FEOL         = true # front-end-of-line checks
 else
-    FEOL    = true # front-end-of-line checks
+  FEOL         = false
 end
-if $beol == "0"
-    BEOL    = false # back-end-of-line checks
+
+if $beol == "1"         || $beol == "true"
+  BEOL         = true # back-end-of-line checks
 else
-    BEOL    = true # back-end-of-line checks
+  BEOL         = false
 end
-if $offgrid == "0"
-    OFFGRID = false # manufacturing grid/angle checks
+
+if $offgrid == "1"      || $offgrid == "true"
+  OFFGRID      = true # manufacturing grid/angle checks
 else
-    OFFGRID = true # manufacturing grid/angle checks
+  OFFGRID      = false
+end
+
+if $seal  == "1"        || $seal == "true"
+  SEAL         = true # SEAL RING checks
+else
+  SEAL         = false
+end
+
+if $floating_met == "1" || $floating_met == "true"
+  FLOATING_MET = true # back-end-of-line checks
+else
+  FLOATING_MET = false
 end
 
 # klayout setup
@@ -241,7 +255,7 @@
 diff_width = diff.rectangles.width(0.15, euclidian).polygons
 diff_cross_areaid_ce = diff_width.edges.outside_part(areaid_ce).not(diff_width.outside(areaid_ce).edges)
 diff_cross_areaid_ce.output("difftap.1", "difftap.1 : min. diff width across areaid:ce : 0.15um")
-diff.not(areaid_ce).width(0.15, euclidian).output("difftap.1_a", "difftap.1_a : min. diff width in periphery : 0.15um")
+diff.outside(areaid_ce).width(0.15, euclidian).output("difftap.1_a", "difftap.1_a : min. diff width in periphery : 0.15um")
 log("END: 65/20 (diff)")
 
 log("START: 65/44 (tap)")
@@ -285,8 +299,12 @@
 
 #   licon
 log("START: 66/44 (licon)")
-ringLICON = licon.drc(with_holes > 0)
-rectLICON = licon.not(ringLICON)
+if SEAL
+  ringLICON = licon.drc(with_holes > 0)
+  rectLICON = licon.not(ringLICON)
+else
+  rectLICON = licon
+end
 xfom = difftap.not(poly)
 licon1ToXfom = licon.interacting(licon.and(xfom))
 licon1ToXfom_PERI = licon1ToXfom.not(areaid_ce)
@@ -333,7 +351,7 @@
 linotace = li.not(areaid_ce)
 linotace.width(0.17, euclidian).output("li.1", "li.1 : min. li width : 0.17um")
 # This rule is taking a long time in some slots
-linotace.space(0.17, euclidian).output("li.3", "li.3 : min. li spacing : 0.17um")
+linotace.edges.space(0.17, euclidian).output("li.3", "li.3 : min. li spacing : 0.17um")
 licon_peri = licon.not(areaid_ce)
 li_edges_with_less_enclosure = li.enclosing(licon_peri, 0.08, projection).second_edges
 error_corners = li_edges_with_less_enclosure.width(angle_limit(100.0), 1.dbu)
@@ -345,17 +363,23 @@
 #   ct
 log("START: 67/44 (mcon)")
 mconnotace = mcon.not(areaid_ce)
-ringMCON = mcon.drc(with_holes > 0)
-rectMCON = mcon.not(ringMCON)
+if SEAL
+  ringMCON = mcon.drc(with_holes > 0)
+  rectMCON = mcon.not(ringMCON)
+else
+  rectMCON = mcon
+end
 rectMCON_peri = rectMCON.not(areaid_ce)
 rectMCON.non_rectangles.output("ct.1", "ct.1: non-ring mcon should be rectangular")
 # rectMCON_peri.edges.without_length(0.17).output("ct.1_a/b", "ct.1_a/b : minimum/maximum width of mcon : 0.17um")
 rectMCON_peri.drc(width < 0.17).output("ct.1_a", "ct.1_a : minimum width of mcon : 0.17um")
 rectMCON_peri.drc(length > 0.17).output("ct.1_b", "ct.1_b : maximum length of mcon : 0.17um")
 mcon.space(0.19, euclidian).output("ct.2", "ct.2 : min. mcon spacing : 0.19um")
-ringMCON.width(0.17, euclidian).output("ct.3", "ct.3 : min. width of ring-shaped mcon : 0.17um")
-ringMCON.drc(width >= 0.175).output("ct.3_a", "ct.3_a : max. width of ring-shaped mcon : 0.175um")
-ringMCON.not(areaid_sl).output("ct.3_b", "ct.3_b: ring-shaped mcon must be enclosed by areaid_sl")
+if SEAL
+  ringMCON.width(0.17, euclidian).output("ct.3", "ct.3 : min. width of ring-shaped mcon : 0.17um")
+  ringMCON.drc(width >= 0.175).output("ct.3_a", "ct.3_a : max. width of ring-shaped mcon : 0.175um")
+  ringMCON.not(areaid_sl).output("ct.3_b", "ct.3_b: ring-shaped mcon must be enclosed by areaid_sl")
+end
 mconnotace.not(li).output("ct.4", "ct.4 : mcon should covered by li")
 log("END: 67/44 (mcon)")
 
@@ -385,6 +409,9 @@
 m1.with_area(0..0.083).output("m1.6", "m1.6 : min. m1 area : 0.083um²")
 
 m1.holes.with_area(0..0.14).output("m1.7", "m1.7 : min. m1 with holes area : 0.14um²")
+if FLOATING_MET
+  m1.not_interacting(via.or(mcon)).output("m1.x", "floating met1, must interact with via1")
+end
 
 if backend_flow = AL
   #Could flag false positive, fix would be to add .rectangles for m1
@@ -398,8 +425,13 @@
 #   via
 log("START: 68/44 (via)")
 if backend_flow = AL
-  ringVIA = via.drc(with_holes > 0)
-  rectVIA = via.not(ringVIA)
+  if SEAL
+    ringVIA = via.drc(with_holes > 0)
+    rectVIA = via.not(ringVIA)
+  else
+    rectVIA = via
+  end
+
   via_not_mt = rectVIA.not(areaid_mt)
 
   via_not_mt.non_rectangles.output("via.1a", "via.1a : via outside of moduleCut should be rectangular")
@@ -409,10 +441,11 @@
 
   via.space(0.17, euclidian).output("via.2", "via.2 : min. via spacing : 0.17um")
 
-  ringVIA.width(0.2, euclidian).output("via.3", "via.3 : min. width of ring-shaped via : 0.2um")
-  ringVIA.drc(width >= 0.205).output("via.3_a", "via.3_a : max. width of ring-shaped via : 0.205um")
-
-  ringVIA.not(areaid_sl).output("via.3_b", "via.3_b: ring-shaped via must be enclosed by areaid_sl")
+  if SEAL
+    ringVIA.width(0.2, euclidian).output("via.3", "via.3 : min. width of ring-shaped via : 0.2um")
+    ringVIA.drc(width >= 0.205).output("via.3_a", "via.3_a : max. width of ring-shaped via : 0.205um")
+    ringVIA.not(areaid_sl).output("via.3_b", "via.3_b: ring-shaped via must be enclosed by areaid_sl")
+  end
 
   m1.edges.enclosing(rectVIA.drc(width == 0.15), 0.055, euclidian).output("via.4a", "via.4a : min. m1 enclosure of 0.15um via : 0.055um")
   rectVIA.squares.drc(width == 0.15).not(m1).output("via.4a_a", "via.4a_a : 0.15um via must be enclosed by met1")
@@ -440,7 +473,9 @@
 
 m2.with_area(0..0.0676).output("m2.6", "m2.6 : min. m2 area : 0.0676um²")
 m2.holes.with_area(0..0.14).output("m2.7", "m2.7 : min. m2 holes area : 0.14um²")
-
+if FLOATING_MET
+  m2.not_interacting(via.or(via2)).output("m2.x", "floating met2, must interact with via1 or via2")
+end
 if backend_flow = AL
   m2.enclosing(via_outside_periphery, 0.055, euclidian).output("m2.4", "m2.4 : min. m2 enclosure of via : 0.055um")
   via_outside_periphery.not(m2).output("m2.4_a", "m2.4_a : via in periphery must be enclosed by met2")
@@ -455,16 +490,25 @@
 #   via2
 log("START: 69/44 (via2)")
 if backend_flow = AL
-  ringVIA2 = via2.drc(with_holes > 0)
-  rectVIA2 = via2.not(ringVIA2)
+  if SEAL
+    ringVIA2 = via2.drc(with_holes > 0)
+    rectVIA2 = via2.not(ringVIA2)
+  else
+    rectVIA2 = via2
+  end
+
   via2_not_mt = rectVIA2.not(areaid_mt)
   via2_not_mt.non_rectangles.output("via2.1a", "via2.1a : via2 outside of moduleCut should be rectangular")
   via2_not_mt.width(0.2, euclidian).output("via2.1a_a", "via2.1a_a : min. width of via2 outside of moduleCut : 0.2um")
   via2_not_mt.edges.without_length(nil, 0.2 + 1.dbu).output("via2.1a_b", "via2.1a_b : maximum length of via2 : 0.2um")
   via2.space(0.2, euclidian).output("via2.2", "via2.2 : min. via2 spacing : 0.2um")
-  ringVIA2.width(0.2, euclidian).output("via2.3", "via2.3 : min. width of ring-shaped via2 : 0.2um")
-  ringVIA2.drc(width >= 0.205).output("via2.3_a", "via2.3_a : max. width of ring-shaped via2 : 0.205um")
-  ringVIA2.not(areaid_sl).output("via2.3_b", "via2.3_b: ring-shaped via2 must be enclosed by areaid_sl")
+
+  if SEAL
+    ringVIA2.width(0.2, euclidian).output("via2.3", "via2.3 : min. width of ring-shaped via2 : 0.2um")
+    ringVIA2.drc(width >= 0.205).output("via2.3_a", "via2.3_a : max. width of ring-shaped via2 : 0.205um")
+    ringVIA2.not(areaid_sl).output("via2.3_b", "via2.3_b: ring-shaped via2 must be enclosed by areaid_sl")
+  end
+
   m2.enclosing(via2, 0.04, euclidian).output("via2.4", "via2.4 : min. m2 enclosure of via2 : 0.04um")
   via2.not(m2).output("via2.4_a", "via2.4_a : via must be enclosed by met2")
 
@@ -486,7 +530,9 @@
 non_huge_m3.space(0.3, euclidian).output("m3.2", "m3.2 : min. m3 spacing : 0.3um")
 
 (huge_m3.separation(non_huge_m3, 0.4, euclidian) + huge_m3.space(0.4, euclidian)).output("m3.3cd", "m3.3cd : min. 3um.m3 spacing m3 : 0.4um")
-
+if FLOATING_MET
+  m3.not_interacting(via2.or(via3)).output("m3.x", "floating met3, must interact with via2 or via3")
+end
 if backend_flow = AL
   m3.enclosing(via2, 0.065, euclidian).output("m3.4", "m3.4 : min. m3 enclosure of via2 : 0.065um")
   via2.not(m3).output("m3.4_a", "m3.4_a : via2 must be enclosed by met3")
@@ -496,9 +542,13 @@
 #   via3
 log("START: 70/44 (via3)")
 if backend_flow = AL
+  if SEAL
+    ringVIA3 = via3.drc(with_holes > 0)
+    rectVIA3 = via3.not(ringVIA3)
+  else
+    rectVIA3 = via3
+  end
 
-  ringVIA3 = via3.drc(with_holes > 0)
-  rectVIA3 = via3.not(ringVIA3)
   via3_not_mt = rectVIA3.not(areaid_mt)
   via3_not_mt.non_rectangles.output("via3.1", "via3.1 : via3 outside of moduleCut should be rectangular")
   via3_not_mt.width(0.2, euclidian).output("via3.1_a", "via3.1_a : min. width of via3 outside of moduleCut : 0.2um")
@@ -528,7 +578,9 @@
 m4.with_area(0..0.240).output("m4.4a", "m4.4a : min. m4 area : 0.240um²")
 
 (huge_m4.separation(non_huge_m4, 0.4, euclidian) + huge_m4.space(0.4, euclidian)).output("m4.5ab", "m4.5ab : min. 3um.m4 spacing m4 : 0.4um")
-
+if FLOATING_MET
+  m4.not_interacting(via3.or(via4)).output("m4.x", "floating met3, must interact with via3 or via4")
+end
 if backend_flow = AL
   m4.enclosing(via3, 0.065, euclidian).output("m4.3", "m4.3 : min. m4 enclosure of via3 : 0.065um")
   via3.not(m4).output("m4.3_a", "m4.3_a : via3 must be enclosed by met4")
@@ -537,17 +589,26 @@
 
 #   via4
 log("START: 71/44 (via4)")
-ringVIA4 = via4.drc(with_holes > 0)
-rectVIA4 = via4.not(ringVIA4)
+if SEAL
+  ringVIA4 = via4.drc(with_holes > 0)
+  rectVIA4 = via4.not(ringVIA4)
+else
+  rectVIA4 = via4
+end
+
 via4_not_mt = rectVIA4.not(areaid_mt)
 via4_not_mt.non_rectangles.output("via4.1", "via4.1 : via4 outside of moduleCut should be rectangular")
 rectVIA4.width(0.8, euclidian).output("via4.1_a", "via4.1_a : min. width of via4 outside of moduleCut : 0.8um")
 rectVIA4.drc(length > 0.8).output("via4.1_b", "via4.1_b : maximum length of via4 : 0.8um")
 
 via4.space(0.8, euclidian).polygons.output("via4.2", "via4.2 : min. via4 spacing : 0.8um")
-ringVIA4.width(0.8, euclidian).output("via4.3", "via4.3 : min. width of ring-shaped via4 : 0.8um")
-ringVIA4.drc(width >= 0.805).output("via4.3_a", "via4.3_a : max. width of ring-shaped via4 : 0.805um")
-ringVIA4.not(areaid_sl).output("via4.3_b", "via4.3_b: ring-shaped via4 must be enclosed by areaid_sl")
+
+if SEAL
+  ringVIA4.width(0.8, euclidian).output("via4.3", "via4.3 : min. width of ring-shaped via4 : 0.8um")
+  ringVIA4.drc(width >= 0.805).output("via4.3_a", "via4.3_a : max. width of ring-shaped via4 : 0.805um")
+  ringVIA4.not(areaid_sl).output("via4.3_b", "via4.3_b: ring-shaped via4 must be enclosed by areaid_sl")
+end
+
 m4.enclosing(via4, 0.19, euclidian).output("via4.4", "via4.4 : min. m4 enclosure of via4 : 0.19um")
 rectVIA4.not(m4).output("via4.4_a", "via4.4_a : m4 must enclose all via4")
 log("END: 71/44 (via4)")
@@ -560,7 +621,9 @@
 
 m5.enclosing(via4, 0.31, euclidian).output("m5.3", "m5.3 : min. m5 enclosure of via4 : 0.31um")
 via4.not(m5).output("m5.3_a", "m5.3_a : via must be enclosed by m5")
-
+if FLOATING_MET
+  m5.not_interacting(via4).output("m5.x", "floating met5, must interact with via4")
+end
 m5.with_area(0..4.0).output("m5.4", "m5.4 : min. m5 area : 4.0um²")
 log("END: 72/20 (m5)")