<div class="notebook">

<div class="nb-cell program" data-background="true" data-below="true" name="p1">
:- dynamic(abnormal1/1).
:- discontiguous(abnormal1/1).
:- dynamic(abnormal2/1).
:- discontiguous(abnormal2/1).
feathers(tweety).
flies(X) :- feathers(X), \+ abnormal1(X).
flies(X) :- feathers(X), \+ abnormal2(X).
</div>

<div class="nb-cell query" data-run="onload" name="q1">
flies(tweety), !.
</div>

<div class="nb-cell program" data-background="true" data-below="true" name="p2">
abnormal1(tweety).
</div>

<div class="nb-cell query" data-run="onload" name="q2">
flies(tweety).
</div>

<div class="nb-cell program" data-background="true" data-below="true" name="p3">
abnormal2(tweety).
</div>

<div class="nb-cell query" data-run="onload" name="q3">
flies(tweety).
</div>

</div>