Look let's longfist to the Max. I've taken some time to compile the following. Enjoy,
Many of the Northern systems do their form on an East-West axis. Long fist reportedly being the 'grand-daddy' also uses this embusen.
If you look at the classical longfist forms you will see how elements from the system were used in later form development.
Yi Lu ChaQuan Classical LongFisthttp://www.youtube.com/watch?v=wH5CCqAtcgc
Er Lu ChaQuan Classical LongFisthttp://www.youtube.com/watch?v=fpWELFWecvM
San Lu ChaQuan Classical LongFisthttp://www.youtube.com/watch?v=lOaIi4HB2SM
Look at the differences between the contemporary and the classical forms.
ChangQuan - yi - Contemporaryhttp://www.youtube.com/watch?v=ObiygVWC-1Y
ChangQuan - Er - Contemporaryhttp://www.youtube.com/watch?v=0xFPWNMaeAQ
ChangQuan - San - Contemporaryhttp://www.youtube.com/watch?v=zEllGdmG7K8
ChangQuan - Si - Contemporaryhttp://www.youtube.com/watch?v=nS7zs80tcjk
Youíll see some repetition of the classical longfist throughout the following forms.
Erlu Maifu (2nd Ambush)http://www.youtube.com/watch?v=XFGyGwy38dM
Shaolin taizu changquanhttp://www.youtube.com/watch?v=8Ap1Ee9ftPY
Zhao Changjun - Changquanhttp://www.youtube.com/watch?v=F7Ij5NAOmKs
This basic form Gongli-quan (powerfist) was a form I once studied. It was part of the Chin Woo Association basic forms sets. This set also includes Tam Tuie. A student would study them before they branched out into the individual instructors personal style (so all the association members had the same basics).
Huo Yuanjia was the founder of the Chin Woo Association (guess what current movie is about his efforts?) and the style taught a combination of arts - ďBecause Huo was widely admired as a Chinese national hero, a series of other masters agreed to teach at the school including Eagle Claw master Chen Zizheng, Seven Star Praying Mantis master Luo Guangyu, Xingyi master Geng Xiaguang, and Wu Jianquan, the founder of Wu style Taijiquan. ď from the Winpedia.
Iíve found an older Eagle Claw, Mantis and Northern Shaolin Set that I think lets you see the Longfist influence in part, even with their stylistic differences.
Mantis Taiwan 1964 (1of3) http://www.youtube.com/watch?v=S5XMIQrvinM&mode=related&search=
Northern Shaolin Cross Battle Formhttp://www.youtube.com/watch?v=3_ILMRctJQA
Kungfu Long Fist (Small Cotton Fist)http://video.google.com/videoplay?docid=-5814774077973210441&q=martial+arts+staff&hl=en
Remember too the forms are but a part of each of those systems, extensive two person sets, extensive weapons work (to develop the grip and overall physical ability) and of course sparring practices, all combine for each systems potential.