What I find amazing, is that in levels with 2 gaps, you can design a bridge that works perfectly every time over the first gap, tinker with the brigde over the second gap (without touching the first bridge at all) and suddently the bridge over the first gap fails every time. This should tell you something is seriously wrong with the physics in this game... If this could be fixed, it would make the experience tolerable at least... I don't mind searching for a good solution, but when that solution is invalidated because I changed a bridge over another gap (without the bridges being connected at all) it frustrates me to no end.
my level 15, probably not very good, but it works anyway:
p,10,11;p,1,9;b,4,11;t,13,9;b,5,6;b,10,7;t,3,6;b,1,3;m,5,13,180,3,wwcddroluuwwwwww;m,4,13,0,2,wwwwcldourwwwwww;m,3,13,180,1,wwwwcruuoddlwwww;m,1,11,90,1,crrollwwwwcrroll;m,10,13,180,2,wwwwwwwjcdroluww;m,11,13,0,1,wwwwwwwjclor;m,10,9,180,1,rollwwcr;m,13,7,180,1,olwwwwcr;m,13,11,90,1,wwwwwwwjwwcllorr;m,5,9,180,3,wwwwucdodcuoucdo;m,4,9,180,2,rodrrwwcurwwrwwl;m,1,6,0,2,wc1uww2ldorwwwww;m,8,7,0,1,wc1llorrwcluodrw;m,4,3,270,1,lrr22uouwwwwcddl;
my level 11, pretty efficient i think? c,3,11;b,6,9;b,3,7;b,9,7;p,9,11;m,10,13,0,2,cldoru;m,7,11,90,1,cwlowr;m,3,9,90,1,wjcluordwwwwww;m,3,13,180,1,crolwwwwwwww;m,1,7,90,1,wcrrror;m,1,11,90,1,wwwwwwcrrollw;m,7,6,180,2,jwwwwwwcru11old;m,11,9,180,3,wjwwwc2rddouul;m,9,9,90,1,wwjcrolwwcrroll;m,7,7,0,2,wwjcdl1luorrwww;
 "Cargo Bridge"){kind=icon}
 "The Codex of Alchemical Engineering"){kind=icon}