diff --git a/2015/07/input.txt b/2015/07/input.txt
new file mode 100644
index 0000000..0fd2859
--- /dev/null
+++ b/2015/07/input.txt
@@ -0,0 +1,339 @@
+lf AND lq -> ls
+iu RSHIFT 1 -> jn
+bo OR bu -> bv
+gj RSHIFT 1 -> hc
+et RSHIFT 2 -> eu
+bv AND bx -> by
+is OR it -> iu
+b OR n -> o
+gf OR ge -> gg
+NOT kt -> ku
+ea AND eb -> ed
+kl OR kr -> ks
+hi AND hk -> hl
+au AND av -> ax
+lf RSHIFT 2 -> lg
+dd RSHIFT 3 -> df
+eu AND fa -> fc
+df AND dg -> di
+ip LSHIFT 15 -> it
+NOT el -> em
+et OR fe -> ff
+fj LSHIFT 15 -> fn
+t OR s -> u
+ly OR lz -> ma
+ko AND kq -> kr
+NOT fx -> fy
+et RSHIFT 1 -> fm
+eu OR fa -> fb
+dd RSHIFT 2 -> de
+NOT go -> gp
+kb AND kd -> ke
+hg OR hh -> hi
+jm LSHIFT 1 -> kg
+NOT cn -> co
+jp RSHIFT 2 -> jq
+jp RSHIFT 5 -> js
+1 AND io -> ip
+eo LSHIFT 15 -> es
+1 AND jj -> jk
+g AND i -> j
+ci RSHIFT 3 -> ck
+gn AND gp -> gq
+fs AND fu -> fv
+lj AND ll -> lm
+jk LSHIFT 15 -> jo
+iu RSHIFT 3 -> iw
+NOT ii -> ij
+1 AND cc -> cd
+bn RSHIFT 3 -> bp
+NOT gw -> gx
+NOT ft -> fu
+jn OR jo -> jp
+iv OR jb -> jc
+hv OR hu -> hw
+19138 -> b
+gj RSHIFT 5 -> gm
+hq AND hs -> ht
+dy RSHIFT 1 -> er
+ao OR an -> ap
+ld OR le -> lf
+bk LSHIFT 1 -> ce
+bz AND cb -> cc
+bi LSHIFT 15 -> bm
+il AND in -> io
+af AND ah -> ai
+as RSHIFT 1 -> bl
+lf RSHIFT 3 -> lh
+er OR es -> et
+NOT ax -> ay
+ci RSHIFT 1 -> db
+et AND fe -> fg
+lg OR lm -> ln
+k AND m -> n
+hz RSHIFT 2 -> ia
+kh LSHIFT 1 -> lb
+NOT ey -> ez
+NOT di -> dj
+dz OR ef -> eg
+lx -> a
+NOT iz -> ja
+gz LSHIFT 15 -> hd
+ce OR cd -> cf
+fq AND fr -> ft
+at AND az -> bb
+ha OR gz -> hb
+fp AND fv -> fx
+NOT gb -> gc
+ia AND ig -> ii
+gl OR gm -> gn
+0 -> c
+NOT ca -> cb
+bn RSHIFT 1 -> cg
+c LSHIFT 1 -> t
+iw OR ix -> iy
+kg OR kf -> kh
+dy OR ej -> ek
+km AND kn -> kp
+NOT fc -> fd
+hz RSHIFT 3 -> ib
+NOT dq -> dr
+NOT fg -> fh
+dy RSHIFT 2 -> dz
+kk RSHIFT 2 -> kl
+1 AND fi -> fj
+NOT hr -> hs
+jp RSHIFT 1 -> ki
+bl OR bm -> bn
+1 AND gy -> gz
+gr AND gt -> gu
+db OR dc -> dd
+de OR dk -> dl
+as RSHIFT 5 -> av
+lf RSHIFT 5 -> li
+hm AND ho -> hp
+cg OR ch -> ci
+gj AND gu -> gw
+ge LSHIFT 15 -> gi
+e OR f -> g
+fp OR fv -> fw
+fb AND fd -> fe
+cd LSHIFT 15 -> ch
+b RSHIFT 1 -> v
+at OR az -> ba
+bn RSHIFT 2 -> bo
+lh AND li -> lk
+dl AND dn -> do
+eg AND ei -> ej
+ex AND ez -> fa
+NOT kp -> kq
+NOT lk -> ll
+x AND ai -> ak
+jp OR ka -> kb
+NOT jd -> je
+iy AND ja -> jb
+jp RSHIFT 3 -> jr
+fo OR fz -> ga
+df OR dg -> dh
+gj RSHIFT 2 -> gk
+gj OR gu -> gv
+NOT jh -> ji
+ap LSHIFT 1 -> bj
+NOT ls -> lt
+ir LSHIFT 1 -> jl
+bn AND by -> ca
+lv LSHIFT 15 -> lz
+ba AND bc -> bd
+cy LSHIFT 15 -> dc
+ln AND lp -> lq
+x RSHIFT 1 -> aq
+gk OR gq -> gr
+NOT kx -> ky
+jg AND ji -> jj
+bn OR by -> bz
+fl LSHIFT 1 -> gf
+bp OR bq -> br
+he OR hp -> hq
+et RSHIFT 5 -> ew
+iu RSHIFT 2 -> iv
+gl AND gm -> go
+x OR ai -> aj
+hc OR hd -> he
+lg AND lm -> lo
+lh OR li -> lj
+da LSHIFT 1 -> du
+fo RSHIFT 2 -> fp
+gk AND gq -> gs
+bj OR bi -> bk
+lf OR lq -> lr
+cj AND cp -> cr
+hu LSHIFT 15 -> hy
+1 AND bh -> bi
+fo RSHIFT 3 -> fq
+NOT lo -> lp
+hw LSHIFT 1 -> iq
+dd RSHIFT 1 -> dw
+dt LSHIFT 15 -> dx
+dy AND ej -> el
+an LSHIFT 15 -> ar
+aq OR ar -> as
+1 AND r -> s
+fw AND fy -> fz
+NOT im -> in
+et RSHIFT 3 -> ev
+1 AND ds -> dt
+ec AND ee -> ef
+NOT ak -> al
+jl OR jk -> jm
+1 AND en -> eo
+lb OR la -> lc
+iu AND jf -> jh
+iu RSHIFT 5 -> ix
+bo AND bu -> bw
+cz OR cy -> da
+iv AND jb -> jd
+iw AND ix -> iz
+lf RSHIFT 1 -> ly
+iu OR jf -> jg
+NOT dm -> dn
+lw OR lv -> lx
+gg LSHIFT 1 -> ha
+lr AND lt -> lu
+fm OR fn -> fo
+he RSHIFT 3 -> hg
+aj AND al -> am
+1 AND kz -> la
+dy RSHIFT 5 -> eb
+jc AND je -> jf
+cm AND co -> cp
+gv AND gx -> gy
+ev OR ew -> ex
+jp AND ka -> kc
+fk OR fj -> fl
+dy RSHIFT 3 -> ea
+NOT bs -> bt
+NOT ag -> ah
+dz AND ef -> eh
+cf LSHIFT 1 -> cz
+NOT cv -> cw
+1 AND cx -> cy
+de AND dk -> dm
+ck AND cl -> cn
+x RSHIFT 5 -> aa
+dv LSHIFT 1 -> ep
+he RSHIFT 2 -> hf
+NOT bw -> bx
+ck OR cl -> cm
+bp AND bq -> bs
+as OR bd -> be
+he AND hp -> hr
+ev AND ew -> ey
+1 AND lu -> lv
+kk RSHIFT 3 -> km
+b AND n -> p
+NOT kc -> kd
+lc LSHIFT 1 -> lw
+km OR kn -> ko
+id AND if -> ig
+ih AND ij -> ik
+jr AND js -> ju
+ci RSHIFT 5 -> cl
+hz RSHIFT 1 -> is
+1 AND ke -> kf
+NOT gs -> gt
+aw AND ay -> az
+x RSHIFT 2 -> y
+ab AND ad -> ae
+ff AND fh -> fi
+ci AND ct -> cv
+eq LSHIFT 1 -> fk
+gj RSHIFT 3 -> gl
+u LSHIFT 1 -> ao
+NOT bb -> bc
+NOT hj -> hk
+kw AND ky -> kz
+as AND bd -> bf
+dw OR dx -> dy
+br AND bt -> bu
+kk AND kv -> kx
+ep OR eo -> eq
+he RSHIFT 1 -> hx
+ki OR kj -> kk
+NOT ju -> jv
+ek AND em -> en
+kk RSHIFT 5 -> kn
+NOT eh -> ei
+hx OR hy -> hz
+ea OR eb -> ec
+s LSHIFT 15 -> w
+fo RSHIFT 1 -> gh
+kk OR kv -> kw
+bn RSHIFT 5 -> bq
+NOT ed -> ee
+1 AND ht -> hu
+cu AND cw -> cx
+b RSHIFT 5 -> f
+kl AND kr -> kt
+iq OR ip -> ir
+ci RSHIFT 2 -> cj
+cj OR cp -> cq
+o AND q -> r
+dd RSHIFT 5 -> dg
+b RSHIFT 2 -> d
+ks AND ku -> kv
+b RSHIFT 3 -> e
+d OR j -> k
+NOT p -> q
+NOT cr -> cs
+du OR dt -> dv
+kf LSHIFT 15 -> kj
+NOT ac -> ad
+fo RSHIFT 5 -> fr
+hz OR ik -> il
+jx AND jz -> ka
+gh OR gi -> gj
+kk RSHIFT 1 -> ld
+hz RSHIFT 5 -> ic
+as RSHIFT 2 -> at
+NOT jy -> jz
+1 AND am -> an
+ci OR ct -> cu
+hg AND hh -> hj
+jq OR jw -> jx
+v OR w -> x
+la LSHIFT 15 -> le
+dh AND dj -> dk
+dp AND dr -> ds
+jq AND jw -> jy
+au OR av -> aw
+NOT bf -> bg
+z OR aa -> ab
+ga AND gc -> gd
+hz AND ik -> im
+jt AND jv -> jw
+z AND aa -> ac
+jr OR js -> jt
+hb LSHIFT 1 -> hv
+hf OR hl -> hm
+ib OR ic -> id
+fq OR fr -> fs
+cq AND cs -> ct
+ia OR ig -> ih
+dd OR do -> dp
+d AND j -> l
+ib AND ic -> ie
+as RSHIFT 3 -> au
+be AND bg -> bh
+dd AND do -> dq
+NOT l -> m
+1 AND gd -> ge
+y AND ae -> ag
+fo AND fz -> gb
+NOT ie -> if
+e AND f -> h
+x RSHIFT 3 -> z
+y OR ae -> af
+hf AND hl -> hn
+NOT h -> i
+NOT hn -> ho
+he RSHIFT 5 -> hh
diff --git a/2015/07/wires.pl b/2015/07/wires.pl
new file mode 100644
index 0000000..0f994c7
--- /dev/null
+++ b/2015/07/wires.pl
@@ -0,0 +1,35 @@
+use 5.20.0;
+use experimental 'signatures';
+
+my %wire;
+
+while(<>) {
+    chomp;
+    my( $instructions, $wire ) = split /\s*->\s*/;
+    $wire{$wire} = $instructions;
+}
+
+say resolve('a');
+
+my %seen;
+sub resolve($key,@cycle) {
+    die "@cycle" if $key ~~ @cycle;
+    push @cycle, $key;
+    my $code = $wire{$key};
+    #warn $code;
+
+    $code =~ s/\b([a-z]+)\b/resolve($1,@cycle)/ge
+        or warn "end of the line $key";
+
+    $code =~ s/NOT/~/;
+    $code =~ s/LSHIFT/<</;
+    $code =~ s/RSHIFT/>>/;
+    $code =~ s/OR/|/;
+    $code =~ s/AND/&/;
+
+    die $code if $code =~ /[A-Z]/;
+
+    warn $key, ' -> ', $code;
+    $wire{$key} = eval( $code ) || 0;
+}
+
diff --git a/2015/07/wires2.pl b/2015/07/wires2.pl
new file mode 100644
index 0000000..e57e668
--- /dev/null
+++ b/2015/07/wires2.pl
@@ -0,0 +1,36 @@
+use 5.20.0;
+use experimental 'signatures';
+
+my %wire;
+
+while(<>) {
+    chomp;
+    my( $instructions, $wire ) = split /\s*->\s*/;
+    $wire{$wire} = $instructions;
+}
+
+my %copy = %wire;
+%wire = ( %copy, b => resolve('a') );
+say resolve('a');
+
+sub resolve($key,@cycle) {
+    die "@cycle" if $key ~~ @cycle;
+    push @cycle, $key;
+    my $code = $wire{$key};
+    #warn $code;
+
+    $code =~ s/\b([a-z]+)\b/resolve($1,@cycle)/ge
+        or warn "end of the line $key";
+
+    $code =~ s/NOT/~/;
+    $code =~ s/LSHIFT/<</;
+    $code =~ s/RSHIFT/>>/;
+    $code =~ s/OR/|/;
+    $code =~ s/AND/&/;
+
+    die $code if $code =~ /[A-Z]/;
+
+    warn $key, ' -> ', $code;
+    $wire{$key} = eval( $code ) || 0;
+}
+