pagre -gre- gismu

x1 passes through/penetrates barrier/medium/portal x2 to destination side x3 from origin side x4.

Passing through in both directions (= rolfargre, pagre ... .i so'ivo'ivo'u (and vice versa)). See also bitmu, denci, ganlo, kalri, vorme, pluta, canko, ragve.

In notes:

x1 is a wall/fence separating x2 and x3 (unordered) of/in structure x4.
x1 is a window/portal/opening [portal] in wall/building/structure x2.
x1 is a/the tooth [body-part] of x2; (adjective:) x1 is dental.
x1 (portal/passage/entrance-way) is closed/shut/not open, preventing passage/access to x2 by x3 (something being blocked).
x1 (portal/passage/entrance-way) is open/ajar/not shut permitting passage/access to x2 by x3.
x1 is a route/path/way/course/track to x2 from x3 via/defined by points including x4 (set).
x1 is located across/on the other side of gap/boundary x2 from x3; x1 is opposite (fi) x3.
x1 is a doorway/gateway/access way between x2 and x3 of structure x4.
x1=k1 is a hole in x2=k2=p2 to/between x3=p3 from/and x4=p4 permitting passage by x5=p1.
x1=p1=k1 passes through portal/generically exits or enters via portal (entrance/exit) x2=p2 to destination side x3=p3=k2 from origin side x4=p4=k3 via route x5=k4 using means/vehicle x6=k5.
t1 controls g1=t2 who crosses g2=k1 to g3=k2 from g4=k2.
p1=l1 passes by p2 to p3 from p4 by l2.
c1=p1 climbs/clambers/creeps/crawls on barrier/portal c2=p2 to destination side p3 from origin side p4 using c4 [limbs/tools]
c1=r1 looks at/examines/views/inspects/regards/watches/gazes at c2=r3 through gap/see-through boundary r2
x1=p1 is cross-country of/crosses terrain x2=p2=t1 to destination side x3=p3 from origin side x4=p4.
g1 is a door/gate (movable barrier) in portal/doorway (opening) v1=g2 between v2 and v3, in structure v4.
kai'i (exp!)
Property relativizing determiner / unary quantifier constructor. {kai'i} introduces a predicate whose first argument slot becomes filled by the property made by taking the bridi in which this {kai'i} appears and putting {ce'u} into the argument slot in which this {kai'i} argument was located. Put formally, "kai'i brodi cu brodu" = "lo ka ce'u brodu cu brodi". Additionally, a {kai'i} term has a rightward logical scope, like quantifiers and adverbials.
lu'ei (exp!)
convert a grammatical quotation to a tanru unit; x1 expresses/says the quoted text for audience x2 via expressive medium x3.
x1 (linear manifold, vector, etc.) is/lies secant to x2 (object, surface, curve, manifold, etc.) passing through or toward points/loci x3 (set of intersected points), by standard/definition/in system x4.