# Because on two groups of identical blocks one works and one doesn't

**URL:** <https://community.thunkable.com/t/because-on-two-groups-of-identical-blocks-one-works-and-one-doesnt/765764>\
**Category:** Questions about Thunkable X\
**Tags:** beginner\
**Created:** [August 24, 2020, 4:06pm UTC](https://community.thunkable.com/t/because-on-two-groups-of-identical-blocks-one-works-and-one-doesnt/765764 "2020-08-24T16:06:27Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![iaia](https://avatars.discourse-cdn.com/v4/letter/i/2bfe46/32.png) [@iaia](https://community.thunkable.com/u/iaia)\
**Post date:** [August 24, 2020, 4:06pm UTC](https://community.thunkable.com/t/because-on-two-groups-of-identical-blocks-one-works-and-one-doesnt/765764/1 "2020-08-24T16:06:27Z")

</div>

Translated with Google.  
Hello, I’m doing a small photo gallery, I don’t understand why the blocks of the first section work while those of the second don’t.

 ![ParagoneFoto](https://us1.discourse-cdn.com/flex015/uploads/thunkable/original/3X/f/0/f04314ae8068d64b9bf6d3817701ea3410e7386a.png)

---

<div class="post-metadata">

**Author:** ![actech](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@actech](https://community.thunkable.com/u/actech)\
**Post date:** [August 25, 2020, 5:48am UTC](https://community.thunkable.com/t/because-on-two-groups-of-identical-blocks-one-works-and-one-doesnt/765764/2 "2020-08-25T05:48:59Z")

</div>

Your blocks have no protection against incorrect data or handling erroneous situations, and you ask why it doesn’t work?

Display the contents of all the blocks that data passes through on the screen, and you will see an error.

---

<div class="post-metadata">

**Author:** ![gobassky](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/gobassky/32/77019_2.png) [@gobassky](https://community.thunkable.com/u/gobassky)\
**Post date:** [August 25, 2020, 8:53am UTC](https://community.thunkable.com/t/because-on-two-groups-of-identical-blocks-one-works-and-one-doesnt/765764/3 "2020-08-25T08:53:41Z")

</div>

You shouldn’t have 2 “screen starts” with different contents… not sure how code compiler will execute these instructions when screen starts.

---

<div class="post-metadata">

**Author:** ![ioannis](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/ioannis/32/146956_2.png) [@ioannis](https://community.thunkable.com/u/ioannis)\
**Post date:** [November 8, 2024, 12:24pm UTC](https://community.thunkable.com/t/because-on-two-groups-of-identical-blocks-one-works-and-one-doesnt/765764/4 "2024-11-08T12:24:40Z")

</div>