Usually Twig only supports one single statement per block:
{% if kategorie=="business" %}
{% set farbe="#800000" %}
{% set align="right" %}
{% set spalten=3 %}
{% endif %}
As you can see, this gets quite verbose and confusing quickly as soon as you have more than just a few consecutive statements. DrupalX adds the ability to combine multiple statements - separated by the usual semi-colon you know from PHP:
{%
if kategorie=="business";
set farbe="#800000";
set align="right";
set spalten=3;
endif;
%}