diff --git a/2017/d1.rkt b/2017/d1.rkt
new file mode 100644
index 0000000..1ac7634
--- /dev/null
+++ b/2017/d1.rkt
@@ -0,0 +1,23 @@
+#lang br/quicklang
+(require sugar/list)
+
+(module+ reader
+  (require syntax/strip-context)
+  (provide read-syntax)
+  (define (read-syntax path port)
+    (strip-context #`(module day1 aoc-racket/2017/d1
+                       #,@(for/list ([datum (in-port read port)])
+                            datum)))))
+
+(provide (rename-out [mb #%module-begin]))
+(define-macro (mb SELECTOR CAPTCHA-STR ...)
+  #'(#%module-begin (captcha-sum 'SELECTOR CAPTCHA-STR) ...))
+
+(define (captcha-sum offset-sig num)
+  (define digits (for/list ([c (in-string (number->string num))])
+                 (string->number (string c))))
+  (define offset (if (eq? offset-sig '★) -1 (/ (length digits) 2)))
+  (for/sum ([first (in-list digits)]
+            [second (in-list (shift-cycle digits offset))]
+            #:when (= first second))
+    first))
\ No newline at end of file
diff --git a/2017/d1/star1.rkt b/2017/d1/star1.rkt
new file mode 100644
index 0000000..7dfbfc8
--- /dev/null
+++ b/2017/d1/star1.rkt
@@ -0,0 +1,2 @@
+#lang aoc-racket/2017/d1 ★
+9513446799636685297929646689682997114316733445451534532351778534251427172168183621874641711534917291674333857423799375512628489423332297538215855176592633692631974822259161766238385922277893623911332569448978771948316155868781496698895492971356383996932885518732997624253678694279666572149831616312497994856288871586777793459926952491318336997159553714584541897294117487641872629796825583725975692264125865827534677223541484795877371955124463989228886498682421539667224963783616245646832154384756663251487668681425754536722827563651327524674183443696227523828832466473538347472991998913211857749878157579176457395375632995576569388455888156465451723693767887681392547189273391948632726499868313747261828186732986628365773728583387184112323696592536446536231376615949825166773536471531487969852535699774113163667286537193767515119362865141925612849443983484245268194842563154567638354645735331855896155142741664246715666899824364722914296492444672653852387389477634257768229772399416521198625393426443499223611843766134883441223328256883497423324753229392393974622181429913535973327323952241674979677481518733692544535323219895684629719868384266425386835539719237716339198485163916562434854579365958111931354576991558771236977242668756782139961638347251644828724786827751748399123668854393894787851872256667336215726674348886747128237416273154988619267824361227888751562445622387695218161341884756795223464751862965655559143779425283154533252573949165492138175581615176611845489857169132936848668646319955661492488428427435269169173654812114842568381636982389224236455633316898178163297452453296667661849622174541778669494388167451186352488555379581934999276412919598411422973399319799937518713422398874326665375216437246445791623283898584648278989674418242112957668397484671119761553847275799873495363759266296477844157237423239163559391553961176475377151369399646747881452252547741718734949967752564774161341784833521492494243662658471121369649641815562327698395293573991648351369767162642763475561544795982183714447737149239846151871434656618825566387329765118727515699213962477996399781652131918996434125559698427945714572488376342126989157872118279163127742349
\ No newline at end of file
diff --git a/2017/d1/star2.rkt b/2017/d1/star2.rkt
new file mode 100644
index 0000000..4cab9c5
--- /dev/null
+++ b/2017/d1/star2.rkt
@@ -0,0 +1,2 @@
+#lang aoc-racket/2017/d1 ★★
+9513446799636685297929646689682997114316733445451534532351778534251427172168183621874641711534917291674333857423799375512628489423332297538215855176592633692631974822259161766238385922277893623911332569448978771948316155868781496698895492971356383996932885518732997624253678694279666572149831616312497994856288871586777793459926952491318336997159553714584541897294117487641872629796825583725975692264125865827534677223541484795877371955124463989228886498682421539667224963783616245646832154384756663251487668681425754536722827563651327524674183443696227523828832466473538347472991998913211857749878157579176457395375632995576569388455888156465451723693767887681392547189273391948632726499868313747261828186732986628365773728583387184112323696592536446536231376615949825166773536471531487969852535699774113163667286537193767515119362865141925612849443983484245268194842563154567638354645735331855896155142741664246715666899824364722914296492444672653852387389477634257768229772399416521198625393426443499223611843766134883441223328256883497423324753229392393974622181429913535973327323952241674979677481518733692544535323219895684629719868384266425386835539719237716339198485163916562434854579365958111931354576991558771236977242668756782139961638347251644828724786827751748399123668854393894787851872256667336215726674348886747128237416273154988619267824361227888751562445622387695218161341884756795223464751862965655559143779425283154533252573949165492138175581615176611845489857169132936848668646319955661492488428427435269169173654812114842568381636982389224236455633316898178163297452453296667661849622174541778669494388167451186352488555379581934999276412919598411422973399319799937518713422398874326665375216437246445791623283898584648278989674418242112957668397484671119761553847275799873495363759266296477844157237423239163559391553961176475377151369399646747881452252547741718734949967752564774161341784833521492494243662658471121369649641815562327698395293573991648351369767162642763475561544795982183714447737149239846151871434656618825566387329765118727515699213962477996399781652131918996434125559698427945714572488376342126989157872118279163127742349
\ No newline at end of file
diff --git a/2017/d1/t1.rkt b/2017/d1/t1.rkt
new file mode 100644
index 0000000..8093e99
--- /dev/null
+++ b/2017/d1/t1.rkt
@@ -0,0 +1,6 @@
+#lang reader "day1.rkt" first
+
+1122
+1111
+1234
+91212129
\ No newline at end of file
diff --git a/2017/d1/t2.rkt b/2017/d1/t2.rkt
new file mode 100644
index 0000000..02455e8
--- /dev/null
+++ b/2017/d1/t2.rkt
@@ -0,0 +1,7 @@
+#lang reader "day1.rkt" second
+
+1212
+1221 
+123425
+123123
+12131415
\ No newline at end of file