zaphod77's page

It's pretty clear. for ranged attacks, if there is a color that stops the attack left, then the attack is stopped.

Melee attacks count as passing through the wall.

The book states that the violet effect makes all others redundant. This applies to the blocking effect.

For attacks from outside the wall, the violet and the matching color both block it. If the attacker has spell resistance, two caster level checks are needed to penetrate the wall. Without it, there is no hope to pierce it without bringing down the entire wall.

For melee attacks or otherwise passing through the wall, each color is applied in order, requiring seven caster level checks and seven saves to resist all the colors. If the damage or poison kills you, the stone effect is automatic, as the spell doesn't say LIVING creature, and only a living one gets to save. If killed or stoned before you get to the insanity effect, the insanity effect is useless. The plane shift effect automatically works unless the poor sap is still alive after dealing with the other colors, then it can be saved against or resisted. Without spell resistance, the poor sap trying to go through takes a minimum of 70 damage (unless he has evasion), has to survive the poison, save vs the flesh to stone spell, save vs insanity, and if still alive and not a statue, save vs the plane shift.