diff --git a/OUTPUT b/OUTPUT
index 86fd548..8a1fb49 100644
--- a/OUTPUT
+++ b/OUTPUT
@@ -381,3 +381,21 @@ ex2.bash : res=650080463519
 ex2-c : res=650080463519
 	time: 0:00.00 real, 0.00 user, 0.00 sys
 	context-switch:	0+1, page-faults: 0+71
+
+=========================================
+================= day17 =================
+=========================================
+
++++++++++++++++++ ex1
+ex1-v1.bash : res=263
+	time: 1:25.64 real, 61.31 user, 30.44 sys
+	context-switch:	5732+166356, page-faults: 0+7279275
+
+ex1.bash : res=263
+	time: 0:00.40 real, 0.40 user, 0.00 sys
+	context-switch:	41+1, page-faults: 0+315
+
++++++++++++++++++ ex2
+ex2.bash : res=1680
+	time: 0:07.88 real, 7.87 user, 0.00 sys
+	context-switch:	815+1, page-faults: 0+2637
diff --git a/day17/Makefile b/day17/Makefile
index b472b5b..2678d58 100644
--- a/day17/Makefile
+++ b/day17/Makefile
@@ -16,11 +16,12 @@ output:
 compile: ex1-c ex2-c
 
 ex1:
+	@$(TIME) ex1-v1.bash < $(INPUT) 2>&1
 	@$(TIME) ex1.bash < $(INPUT) 2>&1
 	@#$(TIME) ex1-c 2020 < $(INPUT) 2>&1
 
 ex2:
-	@#$(TIME) ex2.bash < $(INPUT) 2>&1
+	@$(TIME) ex2.bash < $(INPUT) 2>&1
 	@#$(TIME) ex1-c 30000000 < $(INPUT) 2>&1
 
 clean:
diff --git a/day17/OUTPUT b/day17/OUTPUT
index d62d913..f2fbd3f 100644
--- a/day17/OUTPUT
+++ b/day17/OUTPUT
@@ -1,4 +1,11 @@
-ex1.bash : res=263
-	time: 1:24.06 real, 60.13 user, 30.29 sys
-	context-switch:	5369+166373, page-faults: 0+7362621
+ex1-v1.bash : res=263
+	time: 1:25.64 real, 61.31 user, 30.44 sys
+	context-switch:	5732+166356, page-faults: 0+7279275
 
+ex1.bash : res=263
+	time: 0:00.40 real, 0.40 user, 0.00 sys
+	context-switch:	41+1, page-faults: 0+315
+
+ex2.bash : res=1680
+	time: 0:07.88 real, 7.87 user, 0.00 sys
+	context-switch:	815+1, page-faults: 0+2637
diff --git a/day17/README b/day17/README
index 9e568b6..13914eb 100644
--- a/day17/README
+++ b/day17/README
@@ -145,8 +145,6 @@ After the full six-cycle boot process completes, 112 cubes are left in the activ
 Starting with your given initial configuration, simulate six cycles. How many cubes are left in the active state after the sixth cycle?
 
 Your puzzle answer was 263.
-
-The first half of this puzzle is complete! It provides one gold star: *
 --- Part Two ---
 
 For some reason, your simulated results don't match what the experimental energy source engineers expected. Apparently, the pocket dimension actually has four spatial dimensions, not three.
@@ -398,8 +396,12 @@ After the full six-cycle boot process completes, 848 cubes are left in the activ
 
 Starting with your given initial configuration, simulate six cycles in a 4-dimensional space. How many cubes are left in the active state after the sixth cycle?
 
-Answer:
+Your puzzle answer was 1680.
 
-Although it hasn't changed, you can still get your puzzle input.
+Both parts of this puzzle are complete! They provide two gold stars: **
+
+At this point, you should return to your Advent calendar and try another puzzle.
+
+If you still want to see it, you can get your puzzle input.
 
 You can also [Share] this puzzle.
diff --git a/day17/ex1-v1.bash b/day17/ex1-v1.bash
new file mode 100755
index 0000000..e1a9576
--- /dev/null
+++ b/day17/ex1-v1.bash
@@ -0,0 +1,109 @@
+#!/bin/bash
+#
+# ex1.bash: Advent2020 game, day 17/game 1.
+
+CMD=${0##*/}
+#shopt -s extglob
+
+declare -A life=()
+declare -i x=-1 y=-1 z=-1 res=0
+declare -i maxx maxy maxz
+
+function print_life() {
+	local -i x=0 y=0 z=0 foundx foundy
+	for ((z=0; z<maxz; ++z)); do
+		foundy=1
+		for ((y=0; y<maxy; ++y)); do
+			foundx=1
+			for ((x=0; x<maxx; ++x)); do
+				if [[ -v life[$x-$y-$z] ]]; then
+					#printf "%d-%d-%d:" $x $y $z
+					printf "%c" ${life["$x-$y-$z"]}
+					foundx=1
+				else
+					printf "%c" "."
+				fi
+			done
+			((foundx==1)) && foundy=1 && printf "\n"
+		done
+		((foundy==1)) && printf "z=%d\n\n" "$z"
+	done
+
+}
+
+function count_neighbors () {
+	local -i x=$1 y=$2 z=$3 x1 y1 z1 count=0
+	local str=""
+
+
+	for ((x1=x-1; x1<x+2; ++x1)); do
+		for ((y1=y-1; y1<y+2; ++y1)); do
+			for ((z1=z-1; z1<z+2; ++z1)); do
+				if ((x1!=x || y1!=y || z1!=z)); then
+					if [[ ${life[$x1-$y1-$z1]} == "#" ]]; then
+						((count++))
+						str="$str $x1-$y1-$z1"
+					fi
+
+				fi
+			done
+		done
+	done
+	#((count)) && printf "neighbours (%d, %d, %d)=%s\n" "$x" "$y" "$z" "$str" >&2
+	echo "$count"
+}
+
+function run_cycle () {
+	local -i x y z count=0
+	local -A lifetmp=()
+
+	for ((x=0; x<maxx; ++x)); do
+		for ((y=0; y<maxy; ++y)); do
+			for ((z=0; z<maxz; ++z)); do
+				count=$(count_neighbors "$x" "$y" "$z")
+				if [[ ${life[$x-$y-$z]} == "#" ]]; then
+					((count!=2 && count!=3)) && lifetmp[$x-$y-$z]="."
+				else
+					((count==3)) && lifetmp[$x-$y-$z]="#"
+				fi
+			done
+		done
+	done
+	for k in "${!lifetmp[@]}"; do
+		life[$k]=${lifetmp[$k]}
+	done
+}
+
+function count_active () {
+	local k
+	local -i count=0
+
+	for k in "${!life[@]}"; do
+		if [[ ${life[$k]} == "#" ]]; then
+			((count++))
+		fi
+	done
+	echo "$count"
+}
+
+x=6; y=6; z=6
+while read -r line; do
+	if ((y==6)); then							  # 1st line
+		((maxx=6+${#line}+6+1))
+		((maxy=maxx))
+		((maxz=maxx))
+	fi
+	for ((j=0; j<${#line}; ++j)); do
+		((curx=x+j))
+		life[$curx-$y-$z]=${line:j:1}
+	done
+	((y++))
+done
+for ((i=0; i<6; ++i)); do
+	run_cycle
+done
+res=$(count_active)
+
+printf "%s : res=%d\n" "$CMD" "$res"
+
+exit 0
diff --git a/day17/ex1.bash b/day17/ex1.bash
index e1a9576..d5f3a8f 100755
--- a/day17/ex1.bash
+++ b/day17/ex1.bash
@@ -7,18 +7,22 @@ CMD=${0##*/}
 
 declare -A life=()
 declare -i x=-1 y=-1 z=-1 res=0
-declare -i maxx maxy maxz
+declare -i max
+declare -i loops=6
 
 function print_life() {
 	local -i x=0 y=0 z=0 foundx foundy
-	for ((z=0; z<maxz; ++z)); do
+	for ((z=0; z<max; ++z)); do
 		foundy=1
-		for ((y=0; y<maxy; ++y)); do
+		for ((y=0; y<max; ++y)); do
 			foundx=1
-			for ((x=0; x<maxx; ++x)); do
-				if [[ -v life[$x-$y-$z] ]]; then
+			for ((x=0; x<max; ++x)); do
+				if [[ -v life["$x-$y-$z"] ]]; then
 					#printf "%d-%d-%d:" $x $y $z
-					printf "%c" ${life["$x-$y-$z"]}
+					if [[ ${life[$x-$y-$z]} != "#" ]]; then
+					   printf "error"
+					fi
+					printf "%c" "${life[$x-$y-$z]}"
 					foundx=1
 				else
 					printf "%c" "."
@@ -31,46 +35,43 @@ function print_life() {
 
 }
 
-function count_neighbors () {
-	local -i x=$1 y=$2 z=$3 x1 y1 z1 count=0
-	local str=""
+function run_cycle () {
+	local -i x y z count=0 x1 y1 z1 v
+	local -A lifetmp=()
+	local -a values
 
 
-	for ((x1=x-1; x1<x+2; ++x1)); do
-		for ((y1=y-1; y1<y+2; ++y1)); do
-			for ((z1=z-1; z1<z+2; ++z1)); do
-				if ((x1!=x || y1!=y || z1!=z)); then
-					if [[ ${life[$x1-$y1-$z1]} == "#" ]]; then
-						((count++))
-						str="$str $x1-$y1-$z1"
+	for k in "${!life[@]}"; do
+		values=(${k//-/ })
+		x=${values[0]}
+		y=${values[1]}
+		z=${values[2]}
+
+		for ((x1=x-1; x1<x+2; ++x1)); do
+			for ((y1=y-1; y1<y+2; ++y1)); do
+				for ((z1=z-1; z1<z+2; ++z1)); do
+					if ((x1!=x || y1!=y || z1!=z)); then
+						((++lifetmp[$x1-$y1-$z1]))
 					fi
-
-				fi
+				done
 			done
 		done
 	done
-	#((count)) && printf "neighbours (%d, %d, %d)=%s\n" "$x" "$y" "$z" "$str" >&2
-	echo "$count"
-}
 
-function run_cycle () {
-	local -i x y z count=0
-	local -A lifetmp=()
-
-	for ((x=0; x<maxx; ++x)); do
-		for ((y=0; y<maxy; ++y)); do
-			for ((z=0; z<maxz; ++z)); do
-				count=$(count_neighbors "$x" "$y" "$z")
-				if [[ ${life[$x-$y-$z]} == "#" ]]; then
-					((count!=2 && count!=3)) && lifetmp[$x-$y-$z]="."
-				else
-					((count==3)) && lifetmp[$x-$y-$z]="#"
-				fi
-			done
-		done
+	# clean elements with no neighbors
+	for k in "${!life[@]}"; do
+		if [[ ! -v lifetmp[$k] ]]; then
+			unset "life[$k]"
+		fi
 	done
 	for k in "${!lifetmp[@]}"; do
-		life[$k]=${lifetmp[$k]}
+		v=${lifetmp[$k]}
+
+		if [[ -v life[$k] ]]; then
+			(( v!=2 && v!=3 )) && unset "life[$k]"
+		else
+			(( v==3 )) && life[$k]="#"
+		fi
 	done
 }
 
@@ -86,23 +87,26 @@ function count_active () {
 	echo "$count"
 }
 
-x=6; y=6; z=6
+x=$loops; y=$loops; z=$loops
+
 while read -r line; do
-	if ((y==6)); then							  # 1st line
-		((maxx=6+${#line}+6+1))
-		((maxy=maxx))
-		((maxz=maxx))
+	if ((y==loops)); then						  # 1st line
+		((max=loops+${#line}+loops+1))
 	fi
 	for ((j=0; j<${#line}; ++j)); do
 		((curx=x+j))
-		life[$curx-$y-$z]=${line:j:1}
+		c=${line:j:1}
+		if [[ $c == "#" ]]; then
+			life[$curx-$y-$z]=$c
+		fi
 	done
 	((y++))
 done
 for ((i=0; i<6; ++i)); do
 	run_cycle
 done
-res=$(count_active)
+#echo "================================="
+res=${#life[@]}
 
 printf "%s : res=%d\n" "$CMD" "$res"
 
diff --git a/day17/ex2.bash b/day17/ex2.bash
new file mode 100755
index 0000000..f3b5897
--- /dev/null
+++ b/day17/ex2.bash
@@ -0,0 +1,74 @@
+#!/bin/bash
+#
+# ex1.bash: Advent2020 game, day 17/game 1.
+
+CMD=${0##*/}
+#shopt -s extglob
+
+declare -A life=()
+declare -i x=-1 y=-1 z=-1 w=-1 res=0
+declare -i loops=6
+
+function run_cycle () {
+	local -i x y z w x1 y1 z1 w1 v
+	local -A lifetmp=()
+	local -a values
+
+
+	for k in "${!life[@]}"; do
+		# shellcheck disable=SC2206
+		values=(${k//-/ })
+		x=${values[0]}
+		y=${values[1]}
+		z=${values[2]}
+		w=${values[3]}
+
+		for ((x1=x-1; x1<x+2; ++x1)); do
+			for ((y1=y-1; y1<y+2; ++y1)); do
+				for ((z1=z-1; z1<z+2; ++z1)); do
+					for ((w1=w-1; w1<w+2; ++w1)); do
+						if ((x1!=x || y1!=y || z1!=z || w1!=w)); then
+							((++lifetmp[$x1-$y1-$z1-$w1]))
+						fi
+					done
+				done
+			done
+		done
+	done
+
+	# clean elements with no neighbors
+	for k in "${!life[@]}"; do
+		if [[ ! -v lifetmp[$k] ]]; then
+			unset "life[$k]"
+		fi
+	done
+	for k in "${!lifetmp[@]}"; do
+		v=${lifetmp[$k]}
+
+		if [[ -v life[$k] ]]; then
+			(( v!=2 && v!=3 )) && unset "life[$k]"
+		else
+			(( v==3 )) && life[$k]="#"
+		fi
+	done
+}
+
+x=$loops; y=$loops; z=$loops; w=$loops
+while read -r line; do
+	for ((j=0; j<${#line}; ++j)); do
+		((curx=x+j))
+		c=${line:j:1}
+		if [[ $c == "#" ]]; then
+			life[$curx-$y-$z-$w]=$c
+		fi
+	done
+	((y++))
+done
+for ((i=0; i<6; ++i)); do
+	run_cycle
+done
+res=${#life[@]}
+
+printf "%s : res=%d\n" "$CMD" "$res"
+
+exit 0