diff --git a/41.md b/41.md
index 503f67c3..c8409df8 100644
--- a/41.md
+++ b/41.md
@@ -1,69 +1,158 @@
-NIP-XX
+NIP-41
 ======
 
-Surveys / polls
+# Surveys / polls / quizzes
 -----------------------------------
 
-`draft` `optional` `require:nip-20` `author:fernandolguevara`
+`draft` `optional` `require:nip-13` `require:nip-57`  `author:fernandolguevara`
 
-The `surv` & `surv-resp` tags enables users to have surveys/polls experiences on the network.
+The `surv` tag & `surv-answer` (kind: `30041`) enables users to have surveys/polls/quizzes experiences on the network.
 
+## Spec
 
-#### Spec
+### surv
 
-##### Message
+To start a survey on the network, an event with one or many 'surv' tags may be created.
 
-```
-tag: surv
-options:
- - <multi|single> allow others to reply with one or multiple options
- - <ttl> TTL (in seconds|timestamp) when surv expires, 0 TTL don't expire
- - [<choice>]: up to 4 choices each limited to 25 chars  
-````
-
-```
-tag: surv-resp
-options:
- - [<choice>]: based on surv type it can have one or multi
-````
-
-##### Relays
-
-One vote per key, relays needs to discard all subsequent votes, as well as invalid requests.
-
-##### Invalid responses
 ```json
-["OK", <event_id>, false, 'ALREADY_ANSWERED'],
-["OK", <event_id>, false, 'EXPIRED'],
-["OK", <event_id>, false, 'SINGLE_OPTION'],
-["OK", <event_id>, false, 'INVALID_OPTION', 'optionX', ...],
+{"tags":[
+  ["surv", "{single|multiple}", "ttl", "(label)", "option 1", "option 2", "option 3", "option 4"]
+  ["nonce", "1", "32"]
+  ["amount", "milli-satoshi value"]
+]}
 ```
 
-#### Example
+#### tags
+- `surv`:
+  - `{single|multiple}`: allow others to reply with single or multiple choice.
+  - `ttl:unix-time`: when survey expires, `0` don't expire.
+  - `(label):string`: if present, clients should use it as surv label.
+  - `option:string`: survey options 
+- `nonce`: if present, pow is mandatory for answer. ref: [13](13.md)
+- `amount`: if present, zap is mandatory for answer. ref: [57](57.md)
+
+### surv-answer
+
+To reply to a survey on the network, an event of kind `30041` is created.
+
+```meta
+["surv-answer", "surv-index", "option-index", ...]
+```
 
 ```json
 {
-    "pubkey": "<pub-key>",
-    "created_at": 1000000000,
-    "kind": 1,
-    "tags": [
-      ["t", "hastag"],
-      ["surv", "<multi|single>", "<ttl>", "option 1", "option 2", "option 3"]
-    ],
-    "content": "#hastag what is your favorite option?",
-    "id": "<event-id>"
-  },
-  {
-    "pubkey": "<pub-key>",
-    "created_at": 1000000000,
-    "kind": 1,
-    "tags": [
-      ["p", "<pub-key-root>", "wss://..."],
-      ["e", "<event-id-root>", "wss://...", "root"],
-      ["t", "tag"],
-      ["surv-resp", "option 1", "option 2"...] // based on root event surv type it can have one or multi 
-    ],
-    "content": "hello #tag\n",
-    "id": "<event-id>"
-  }
+  "kind": 30041,
+  "tags":[
+    ["e", "<event-id-root>", "wss://...", "root"]
+    ["d", "surv-answer/{event-id-root}"]
+    ["surv-answer", "0", "option-index:int", "{...}"]
+    ["nonce", "1", "32"],
+    ["amount", "milli-satoshi value"],
+  ]
+}
 ```
+at least one selected option index should present on the answer event the tag `surv-answer`
+
+tags:
+ - `e`: `<event-id-root>` origin event.
+ - `d`: the value should be an string formed using origin `event-id-root` for the survey.
+ - `surv-answer`:
+   - `surv-index:int`: starting at 0.
+   - `option-index:int`: starting at 0.
+ - `nonce`: if present, pow is mandatory for answer.
+ - `amount`: if present, zap is mandatory for answer.
+
+
+## Relay and client recommendations
+- `surv` tag:
+  - Should have at least `two` options.
+  - The value of the `label` field should allow enough characters to express the questions.
+  - The `options` items should be limited up to 4.
+  - Each `option` should be 25 chars limited.
+
+## Examples
+
+### Example surv single
+
+```json
+{
+  "pubkey": "<pub-key>",
+  "created_at": 1000000000,
+  "kind": 1,
+  "tags": [
+    ["t", "hastag"],
+    ["surv", "single", "0", "", "option 1", "option 2", "options 3"],
+  ],
+  "content": "#hastag what is your favorite option?",
+  "id": "<event-id>"
+},
+{
+  "pubkey": "<pub-key>",
+  "created_at": 1000000000,
+  "kind": 30041,
+  "tags": [
+    ["e", "<event-id-root>", "wss://...", "root"],
+    ["t", "tag"],
+    ["surv-answer", "", "0"]
+  ],
+  "content": "here my favorite option is #option1 \n",
+  "id": "<event-id>"
+}
+```
+
+### Example surv multiple with expiration
+
+```json
+{
+  "pubkey": "<pub-key>",
+  "created_at": 1000000000,
+  "kind": 1,
+  "tags": [
+    ["t", "hastag"],
+    ["surv", "multiple", "1684599600"],
+    ["options", "option 1", "option 2", "options 3"],
+  ],
+  "content": "#hastag what are your favorite options?",
+  "id": "<event-id>"
+},
+{
+  "pubkey": "<pub-key>",
+  "created_at": 1000000000,
+  "kind": 30041,
+  "tags": [
+    ["e", "<event-id-root>", "wss://...", "root"],
+    ["t", "tag"],
+    ["surv-answer", "", "0", "2"]
+  ],
+  "content": "here my favorite option is #option1 \n",
+  "id": "<event-id>"
+}
+```
+### Example multiple surv 
+
+```json
+{
+  "pubkey": "<pub-key>",
+  "created_at": 1000000000,
+  "kind": 1,
+  "tags": [
+    ["t", "hastag"],
+    ["surv", "single", "0", "surv 1?", "option 1", "option 2", "options 3"],
+    ["surv", "multiple", "0", "surv 2?", "option 1", "option 2", "options 3"],
+  ],
+  "content": "#hastag Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do?",
+  "id": "<event-id>"
+},
+{
+  "pubkey": "<pub-key>",
+  "created_at": 1000000000,
+  "kind": 30041,
+  "tags": [
+    ["e", "<event-id-root>", "wss://...", "root"],
+    ["surv-answer", "0", "0"]
+    ["surv-answer", "1", "0", "2"]
+  ],
+  "content": "quis nostrud exercitation ullamco laboris!\n",
+  "id": "<event-id>"
+}
+```
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