🎉 Created a working package with a bare bones working custom environment

.gitignore

@@ -1,3 +1,6 @@
+# general
+**test**
+
 # ---> TeX
 ## Core latex/pdflatex auxiliary files:
 *.aux

cheatsheet.sty

@@ -0,0 +1,81 @@
+\NeedsTeXFormat{LaTeX2e}[2022-06-01]
+\DeclareCurrentRelease{} {2023-10-09}
+
+\RequirePackage{expl3}
+\ProvidesExplPackage{cheatsheet} {2023/10/09} {alpha}
+    {LaTeX package that provides simple commands to put informations of varying formats (tables, math, listings, lists, ...) into visually appealing boxes, like sticky notes.}
+
+%
+% package options  
+%
+
+% \keys_define:nn {cheatsheet} 
+%     {
+%         columns .tl_set:N = \l__cheatsheetboxes_columns_tl
+%     }
+
+%
+% required packages
+%
+
+\RequirePackage{multicol}
+\RequirePackage{rotating}
+%\RequirePackage{tabularray}
+
+%
+% optional packages interoperability
+%
+
+% \AtBeginDocument{
+%  \@ifpackageloaded{xcolor}{\RequirePackage{ninecolors}}{}
+%  \@ifpackageloaded{hyperref}{
+%  \newenvironment{tblrNoHyper}{\NoHyper}{\endNoHyper}
+%  }{
+%  \newenvironment{tblrNoHyper}{}{}
+%  }
+% }
+
+%
+% cheat sheet environment
+%
+
+\int_new:N \l__cheatsheet_rotdeg_int
+\bool_new:N \l__cheatsheet_rotate_bool
+
+\NewDocumentEnvironment { cheatsheet }
+    { O{} b }
+    {%
+        \newpage
+        
+        \int_set:Nn \l__cheatsheet_rotdeg_int {0}
+        \bool_set_false:N \l__cheatsheet_rotate_bool
+        
+        \keys_set:nn { cheatsheet/cheatsheet } { #1 }
+        
+        \bool_if:nT { \l__cheatsheet_clearhf_bool }
+            { \thispagestyle{empty} }
+            
+        \bool_if:nT { \l__cheatsheet_rotate_bool }
+            { \begin{turn}{ \number \l__cheatsheet_rotdeg_int } }
+        
+        #2
+        
+        \bool_if:nT { \l__cheatsheet_rotate_bool }
+            { \end{turn} }
+    }
+    {   }
+    
+ 
+\keys_define:nn { cheatsheet/cheatsheet }
+    {
+        , columns   .int_set:N = \l__cheatsheet_columns_int
+        , columns   .default:n = 2
+        , rotate    .code:n = {%
+            \int_set:Nn \l__cheatsheet_rotdeg_int { \int_mod:nn {#1} {360} }
+            \bool_set_true:N \l__cheatsheet_rotate_bool
+        }
+        , clearhf   .bool_set:N = \l__cheatsheet_clearhf_bool
+        , clearhf   .default:n = false
+    }
+
+\endinput