diff --git a/glyphs/letters-unified-basic.aki b/glyphs/letters-unified-basic.aki
index 0d82ff6..6d299b3 100644
--- a/glyphs/letters-unified-basic.aki
+++ b/glyphs/letters-unified-basic.aki
@@ -127,7 +127,7 @@ symbol-block 'J'
 	create-glyph 'J.straight' : glyph-construction
 		set-width WIDTH
 		include capitalMarks
-		set-anchor 'overlay' BASE (RIGHTSB - STROKE * CORRECTION_HX - JBALANCE2) (CAP * BARPOS)
+		set-anchor 'overlay' BASE (RIGHTSB - STROKE * CORRECTION_HX * 0.75 - JBALANCE2) (CAP * BARPOS)
 		
 		local slope (STROKE * 0.00092)
 		local expand 0.35
@@ -1360,7 +1360,7 @@ symbol-block 'r'
 			alsothru 0.75 0.25
 			straight.down.end (rbar - fine * CORRECTION_HX) (XH * 0.53 + (SMALLSMOOTH - SMALLSMOOTHA)) [widths.heading fine 0 DOWNWARD]
 		include : VBarRight rbar 0 XH
-		set-anchor 'overlay' BASE rbar (XH * 0.5)
+		set-anchor 'overlay' BASE (rbar - STROKE * 0.25) (XH * 0.5)
 		
 		if SLAB : begin
 			include : rBottomSerif 0
diff --git a/glyphs/letters-unified-extended.aki b/glyphs/letters-unified-extended.aki
index 7e0fdb2..7ee2457 100644
--- a/glyphs/letters-unified-extended.aki
+++ b/glyphs/letters-unified-extended.aki
@@ -395,7 +395,7 @@ symbol-block 'pi'
 			flat m2 XH [heading DOWNWARD]
 			curl m2 hook
 			arcvh
-			flat [Math.min (RIGHTSB - HALFSTROKE) (m2 + hook - HALFSTROKE)] HALFSTROKE [heading RIGHTWARD]
+			flat [Math.min (RIGHTSB - STROKE * 0.25) (m2 + hook - HALFSTROKE)] HALFSTROKE [heading RIGHTWARD]
 			curl RIGHTSB HALFSTROKE [heading RIGHTWARD]
 
 define {SigmaShape} : symbol-block 'Sigma'
diff --git a/glyphs/symbol-math.aki b/glyphs/symbol-math.aki
index ac80d16..1eea5af 100644
--- a/glyphs/symbol-math.aki
+++ b/glyphs/symbol-math.aki
@@ -67,9 +67,9 @@ symbol-block 'Letter-like Mathematical Symbols'
 		include : dispiro
 			widths.lhs OPERATORSTROKE
 			flat (RIGHTSB - OX) SMALLSMOOTHA
-			curl (RIGHTSB - OX) (XH - SMALLSMOOTHB)
-			hookend CAPO 0.6
-			g4   [mix SB RIGHTSB 0.075] [mix XH CAP 0.8]
+			curl (RIGHTSB - OX) (CAP - SMALLSMOOTHB)
+			hookend CAPO
+			g4   SB (CAP - HOOK)
 
 symbol-block 'Mathematical Operators'
 	create-glyph 'plus' : glyph-construction
diff --git a/onegroup.mk b/onegroup.mk
index 3bf7ecf..7222222 100644
--- a/onegroup.mk
+++ b/onegroup.mk
@@ -19,8 +19,8 @@ endif
 NODE_FDT = node --expose-gc
 NODE = node
 
-UPRIGHT = $(OBJDIR)/$(PREFIX)-thin.ttf $(OBJDIR)/$(PREFIX)-extralight.ttf $(OBJDIR)/$(PREFIX)-light.ttf $(OBJDIR)/$(PREFIX)-regular.ttf $(OBJDIR)/$(PREFIX)-bold.ttf $(OBJDIR)/$(PREFIX)-heavy.ttf
-ITALIC  = $(OBJDIR)/$(PREFIX)-thinitalic.ttf $(OBJDIR)/$(PREFIX)-extralightitalic.ttf $(OBJDIR)/$(PREFIX)-lightitalic.ttf $(OBJDIR)/$(PREFIX)-italic.ttf $(OBJDIR)/$(PREFIX)-bolditalic.ttf $(OBJDIR)/$(PREFIX)-heavyitalic.ttf
+UPRIGHT = $(OBJDIR)/$(PREFIX)-thin.ttf $(OBJDIR)/$(PREFIX)-extralight.ttf $(OBJDIR)/$(PREFIX)-light.ttf $(OBJDIR)/$(PREFIX)-regular.ttf $(OBJDIR)/$(PREFIX)-medium.ttf $(OBJDIR)/$(PREFIX)-bold.ttf $(OBJDIR)/$(PREFIX)-heavy.ttf
+ITALIC  = $(OBJDIR)/$(PREFIX)-thinitalic.ttf $(OBJDIR)/$(PREFIX)-extralightitalic.ttf $(OBJDIR)/$(PREFIX)-lightitalic.ttf $(OBJDIR)/$(PREFIX)-italic.ttf $(OBJDIR)/$(PREFIX)-mediumitalic.ttf $(OBJDIR)/$(PREFIX)-bolditalic.ttf $(OBJDIR)/$(PREFIX)-heavyitalic.ttf
 EXTUPRG = 
 EXTITAL = 
 OUTPUTS = $(UPRIGHT) $(ITALIC)
@@ -67,6 +67,10 @@ $(OBJDIR)/.pass0-$(PREFIX)-regular.fdt : $(SCRIPTS) | $(OBJDIR)
 	$(NODE_FDT) generate -o $@ iosevka $(STYLE_COMMON) w-book s-upright $(STYLE_UPRIGHT) $(STYLE_SUFFIX)
 $(OBJDIR)/.pass0-$(PREFIX)-italic.fdt : $(SCRIPTS) | $(OBJDIR)
 	$(NODE_FDT) generate -o $@ iosevka $(STYLE_COMMON) w-book s-italic  $(STYLE_ITALIC) $(STYLE_SUFFIX)
+$(OBJDIR)/.pass0-$(PREFIX)-medium.fdt : $(SCRIPTS) | $(OBJDIR)
+	$(NODE_FDT) generate -o $@ iosevka $(STYLE_COMMON) w-medium s-upright $(STYLE_UPRIGHT) $(STYLE_SUFFIX)
+$(OBJDIR)/.pass0-$(PREFIX)-mediumitalic.fdt : $(SCRIPTS) | $(OBJDIR)
+	$(NODE_FDT) generate -o $@ iosevka $(STYLE_COMMON) w-medium s-italic  $(STYLE_ITALIC) $(STYLE_SUFFIX)
 $(OBJDIR)/.pass0-$(PREFIX)-bold.fdt : $(SCRIPTS) | $(OBJDIR)
 	$(NODE_FDT) generate -o $@ iosevka $(STYLE_COMMON) w-bold s-upright $(STYLE_UPRIGHT) $(STYLE_SUFFIX)
 $(OBJDIR)/.pass0-$(PREFIX)-bolditalic.fdt : $(SCRIPTS) | $(OBJDIR)
diff --git a/parameters.toml b/parameters.toml
index e56daa4..7df5474 100644
--- a/parameters.toml
+++ b/parameters.toml
@@ -13,6 +13,7 @@ xheight = 530      # X-height
 #descender = -205  # Unnecessary
 
 contrast = 1.11111 # Stroke width contrast
+essx = 1.12        # Contrast of the middle of 'S'
 
 italicangle = 0    # Slant angle, in degrees
 
@@ -84,7 +85,6 @@ stroke = 18
 sb = 80
 dotsize = 50
 periodsize = 55
-essx = 1.12
 
 cthin = 0.9
 cthinb = 0.9
@@ -98,7 +98,6 @@ stroke = 36
 sb = 72
 dotsize = 70
 periodsize = 77
-essx = 1.12
 
 cthin = 0.75
 cthinb = 0.75
@@ -107,14 +106,10 @@ cthinb = 0.75
 weight = 300
 style = 'Light'
 
-stroke = 54
+stroke = 58
 sb = 63
-dotsize = 90
-periodsize = 99
-essx = 1.12
-
-cthin = 0.75
-cthinb = 0.75
+dotsize = 95
+periodsize = 103
 
 [w-book]
 isBold = false
@@ -125,7 +120,22 @@ sb = 60
 stroke = 72
 dotsize = 125
 periodsize = 140
-essx = 1.12
+
+[w-medium]
+weith = 500
+style = 'Medium'
+
+sb = 50
+stroke = 83
+dotsize = 140
+periodsize = 145
+essx = 1.07
+
+ahook = 127
+hook = 153
+rbalance = 58
+rbalance2 = 19
+smooth = 200
 
 [w-bold]
 isBold = true
@@ -150,7 +160,6 @@ rbalance = 50
 rbalance2 = 25
 rhook = 95
 smooth = 210
-smallsmooth = 230
 jbalance2 = 60
 tbalance = 50
 sbalance = 0.5
@@ -178,7 +187,6 @@ rbalance = 50
 rbalance2 = 25
 rhook = 95
 smooth = 210
-smallsmooth = 230
 jbalance2 = 60
 tbalance = 50
 sbalance = 0.5
diff --git a/support/spirokit.aki b/support/spirokit.aki
index 8431715..18aed26 100644
--- a/support/spirokit.aki
+++ b/support/spirokit.aki
@@ -85,7 +85,7 @@ export : define [SetupBuilders args] : begin
 			fallback raf unimportant
 		return rs
 
-
+	define DEFAULT_STEPS 8
 	define {jhv, jvh} : let [cache {}] : begin
 		local [build samples] : begin
 			local hv {}
@@ -104,8 +104,8 @@ export : define [SetupBuilders args] : begin
 			if [not cache.(samples)] : build samples
 			return cache.(samples).vh
 		list hv vh
-	define [archv samples notiny k raf] : alsothruthem [jhv [fallback samples 12]] raf
-	define [arcvh samples notiny k raf] : alsothruthem [jvh [fallback samples 12]] raf
+	define [archv samples notiny k raf] : alsothruthem [jhv [fallback samples DEFAULT_STEPS]] raf
+	define [arcvh samples notiny k raf] : alsothruthem [jvh [fallback samples DEFAULT_STEPS]] raf
 	
 	define [complexThru] : begin
 		local a : {}.slice.call arguments
@@ -138,6 +138,7 @@ export : define [SetupBuilders args] : begin
 		return {.knots [flatten knots] .closed closed .lastafs lastafs}
 	
 	define QUAD false
+	define PRECISION 1
 	define [dispiro] : begin
 		local s : new SpiroExpansionContext
 		set s.gizmo globalTransform
@@ -152,16 +153,16 @@ export : define [SetupBuilders args] : begin
 		local {.lhs lhs .rhs rhs} : s.expand [fallback s.contrast CONTRAST]
 		if closed : then
 			local g : new Glyph
-			libspiro.spiroToBezierOnContext [lhs.slice 0 (-1)] true g QUAD 0.5
+			libspiro.spiroToBezierOnContext [lhs.slice 0 (-1)] true g QUAD PRECISION
 			local lhsContour g.contours.0
 			set g.contours {}
-			libspiro.spiroToBezierOnContext [rhs.reverse :.slice 0 (-1)] true g QUAD 0.5
+			libspiro.spiroToBezierOnContext [rhs.reverse :.slice 0 (-1)] true g QUAD PRECISION
 			local rhsContour g.contours.0
 			set g.contours {[lhsContour.concat rhsContour]}
 		: else
 			local g : new Glyph
 			lhs.0.type = rhs.0.type = lhs.(lhs.length - 1).type = rhs.(rhs.length - 1).type = 'corner'
-			libspiro.spiroToBezierOnContext [lhs.concat : rhs.reverse] true g QUAD 0.5
+			libspiro.spiroToBezierOnContext [lhs.concat : rhs.reverse] true g QUAD PRECISION
 		set g.knots knots
 		set g.lhsknots lhs
 		set g.rhsknots rhs
diff --git a/testdrive/index.html b/testdrive/index.html
index b3cfda6..443a031 100644
--- a/testdrive/index.html
+++ b/testdrive/index.html
@@ -48,6 +48,17 @@
 			font-style: italic;
 			src: url('assets/iosevka-italic.woff') format('woff'), url('assets/iosevka-italic.ttf') format('truetype');
 		}
+		@font-face {
+			font-family: IosevkaWEB;
+			font-weight: 500;
+			src: url('assets/iosevka-medium.woff') format('woff'), url('assets/iosevka-medium.ttf') format('truetype');
+		}
+		@font-face {
+			font-family: IosevkaWEB;
+			font-style: italic;
+			font-weight: 500;
+			src: url('assets/iosevka-mediumitalic.woff') format('woff'), url('assets/iosevka-mediumitalic.ttf') format('truetype');
+		}
 		@font-face {
 			font-family: IosevkaWEB;
 			font-weight: 700;
@@ -112,6 +123,17 @@
 			font-style: italic;
 			src: url('assets/iosevka-slab-italic.woff') format('woff'), url('assets/iosevka-slab-italic.ttf') format('truetype');
 		}
+		@font-face {
+			font-family: IosevkaSlabWEB;
+			font-weight: 500;
+			src: url('assets/iosevka-slab-medium.woff') format('woff'), url('assets/iosevka-slab-medium.ttf') format('truetype');
+		}
+		@font-face {
+			font-family: IosevkaSlabWEB;
+			font-style: italic;
+			font-weight: 500;
+			src: url('assets/iosevka-slab-mediumitalic.woff') format('woff'), url('assets/iosevka-slab-mediumitalic.ttf') format('truetype');
+		}
 		@font-face {
 			font-family: IosevkaSlabWEB;
 			font-weight: 700;
@@ -170,11 +192,12 @@
 			font-size: 2rem;
 			width: 68rem;
 		}
-		.thin { font-weight: 100 }
+		.thin       { font-weight: 100 }
 		.extralight { font-weight: 200 }
-		.light { font-weight: 300 }
-		.bold { font-weight: 700 }
-		.heavy { font-weight: 900 }
+		.light      { font-weight: 300 }
+		.medium     { font-weight: 500 }
+		.bold       { font-weight: 700 }
+		.heavy      { font-weight: 900 }
 		.italic { font-style: italic }
 		.show table.block {
 			width: 68rem;
@@ -350,6 +373,8 @@
 				{name: 'iosevka-lightitalic', cls:'light italic', display: 'Iosevka Light Italic'}, {name: 'iosevka-slab-lightitalic', cls:'slab light italic', display: 'Iosevka Slab Light Italic'} ],
 			[	{name: 'iosevka-regular', cls: '', display: 'Iosevka'}, {name: 'iosevka-slab-regular', cls: 'slab', display: 'Iosevka Slab'},
 				{name: 'iosevka-italic', cls:'italic', display: 'Iosevka Italic'}, {name: 'iosevka-slab-italic', cls:'slab italic', display: 'Iosevka Slab Italic'} ],
+			[	{name: 'iosevka-medium', cls: 'medium', display: 'Iosevka Medium'}, {name: 'iosevka-slab-medium', cls: 'slab medium', display: 'Iosevka Slab Medium'},
+				{name: 'iosevkamediumitalic', cls:'medium italic', display: 'Iosevka Medium Italic'}, {name: 'iosevka-slab-mediumitalic', cls:'slab medium italic', display: 'Iosevka Slab Medium Italic'} ],
 			[	{name: 'iosevka-bold', cls: 'bold', display: 'Iosevka Bold'}, {name: 'iosevka-slab-bold', cls: 'slab bold', display: 'Iosevka Slab Bold'},
 				{name: 'iosevka-bolditalic', cls:'bold italic', display: 'Iosevka Bold Italic'}, {name: 'iosevka-slab-bolditalic', cls:'slab bold italic', display: 'Iosevka Slab Bold Italic'} ],
 			[	{name: 'iosevka-heavy', cls: 'heavy', display: 'Iosevka Heavy'}, {name: 'iosevka-slab-heavy', cls: 'slab heavy', display: 'Iosevka Slab Heavy'},