diff --git a/Project.toml b/Project.toml
index 645d7b0..6359037 100644
--- a/Project.toml
+++ b/Project.toml
@@ -8,7 +8,9 @@ DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 DefaultApplication = "3f0dd361-4fe0-5fc6-8523-80b14ec94d85"
 EzXML = "8f5d6c58-4d21-5cfd-889c-e3ad7ee6a615"
 FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
+GridLayoutBase = "3955a311-db13-416c-9275-1d80ed98e5e9"
 ImageIO = "82e4d734-157c-48bb-816b-45c225c6df19"
+Observables = "510215fc-4207-5dde-b226-833fc4488ee2"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 XMLDict = "228000da-037f-5747-90a9-8195ccbf91a5"
 ZipArchives = "49080126-0e18-4c2a-b176-c102e4b3760c"
@@ -18,7 +20,9 @@ DataStructures = "0.18"
 DefaultApplication = "1"
 EzXML = "1"
 FileIO = "1"
+GridLayoutBase = "0.11"
 ImageIO = "0.6.1"
+Observables = "0.5"
 Tables = "1"
 XMLDict = "0.4"
 ZipArchives = "2"
diff --git a/src/PPTX.jl b/src/PPTX.jl
index 2db23e6..14880cf 100644
--- a/src/PPTX.jl
+++ b/src/PPTX.jl
@@ -10,8 +10,16 @@ using ZipArchives:
 import Tables
 import Tables: columns, columnnames, rows
 
+import GridLayoutBase
+import GridLayoutBase: GridLayout, LayoutObservables, BBox
+
+import Observables
+import Observables: Observable
+
 export Presentation, Slide, TextBox, Picture, Table
 
+export ShapeLayout
+
 include("AbstractShape.jl")
 include("constants.jl")
 include("TextBox.jl")
@@ -22,5 +30,6 @@ include("Presentation.jl")
 include("xml_utils.jl")
 include("xml_ppt_utils.jl")
 include("write.jl")
+include("layout.jl")
 
 end
diff --git a/src/TextBox.jl b/src/TextBox.jl
index cf44c2e..96759fd 100644
--- a/src/TextBox.jl
+++ b/src/TextBox.jl
@@ -59,10 +59,10 @@ TextBox
 """
 struct TextBox <: AbstractShape
     content::TextBody
-    offset_x::Int # EMUs
-    offset_y::Int # EMUs
-    size_x::Int # EMUs
-    size_y::Int # EMUs
+    offset_x::Observable{Int} # EMUs
+    offset_y::Observable{Int} # EMUs
+    size_x::Observable{Int} # EMUs
+    size_y::Observable{Int} # EMUs
     hlink::Union{Nothing, Any}
     function TextBox(
         content::AbstractString,
@@ -76,10 +76,10 @@ struct TextBox <: AbstractShape
         # input is in mm
         return new(
             TextBody(content, style),
-            Int(round(offset_x * _EMUS_PER_MM)),
-            Int(round(offset_y * _EMUS_PER_MM)),
-            Int(round(size_x * _EMUS_PER_MM)),
-            Int(round(size_y * _EMUS_PER_MM)),
+            Observable(Int(round(offset_x * _EMUS_PER_MM))),
+            Observable(Int(round(offset_y * _EMUS_PER_MM))),
+            Observable(Int(round(size_x * _EMUS_PER_MM))),
+            Observable(Int(round(size_y * _EMUS_PER_MM))),
             hlink
         )
     end
@@ -112,10 +112,10 @@ function _show_string(p::TextBox, compact::Bool)
     show_string = "TextBox"
     if !compact
         show_string *= "\n content is \"$(String(p.content))\""
-        show_string *= "\n offset_x is $(p.offset_x) EMUs"
-        show_string *= "\n offset_y is $(p.offset_y) EMUs"
-        show_string *= "\n size_x is $(p.size_x) EMUs"
-        show_string *= "\n size_y is $(p.size_y) EMUs"
+        show_string *= "\n offset_x is $(p.offset_x[]) EMUs"
+        show_string *= "\n offset_y is $(p.offset_y[]) EMUs"
+        show_string *= "\n size_x is $(p.size_x[]) EMUs"
+        show_string *= "\n size_y is $(p.size_y[]) EMUs"
     end
     return show_string
 end
@@ -145,8 +145,8 @@ function make_xml(t::TextBox, id::Int=1)
 
     nvSpPr = Dict("p:nvSpPr" => [cNvPr, cNvSpPr, nvPr])
 
-    offset = Dict("a:off" => [Dict("x" => "$(t.offset_x)"), Dict("y" => "$(t.offset_y)")])
-    extend = Dict("a:ext" => [Dict("cx" => "$(t.size_x)"), Dict("cy" => "$(t.size_y)")])
+    offset = Dict("a:off" => [Dict("x" => "$(t.offset_x[])"), Dict("y" => "$(t.offset_y[])")])
+    extend = Dict("a:ext" => [Dict("cx" => "$(t.size_x[])"), Dict("cy" => "$(t.size_y[])")])
 
     spPr = Dict(
         "p:spPr" => [
diff --git a/src/layout.jl b/src/layout.jl
new file mode 100644
index 0000000..9bf6c14
--- /dev/null
+++ b/src/layout.jl
@@ -0,0 +1,138 @@
+
+# This struct exists for these reasons: 
+# 1) To add all shapes in the layout as a flat vector in Slide (so id is same as index)
+# 2) To ensure that the only contents of the layout can be AbstractShapes
+# 3) To allow us to override setindex! with an AbstractShape without risk of ambiguity
+# 4) to provide some better default values for the GridLayout (especially the bbox, see below)
+
+# Main drawback is that we don't get all the utility functions defined for GridLayout for free since we must forward
+# the calls. There are also a couple of functions which check x isa GridLayout internally which will not work
+struct ShapeLayout
+    slide::Slide
+    layout::GridLayout
+    function ShapeLayout(
+        slide,
+        offset_x::Real, # millimeters
+        offset_y::Real, # millimeters
+        size_x::Real, # millimeters
+        size_y::Real; # millimeters
+        kwargs...
+        )
+        offset_x_emu = offset_x * _EMUS_PER_MM
+        offset_y_emu = offset_y * _EMUS_PER_MM
+        size_x_emu = size_x * _EMUS_PER_MM
+        size_y_emu = size_y * _EMUS_PER_MM
+
+        # Maybe better for users to see this in mm, but all other shapes display in EMU
+        suggestedbbox = BBox(
+            offset_x_emu,               # Left
+            offset_x_emu + size_x_emu,  # Right
+            -offset_y_emu - size_y_emu, # Bottom. Negative since PPTX counts y from the top
+            -offset_y_emu               # Top. Negative since PPTX counts y from the top
+        )
+
+        new(slide, GridLayout(;halign=:left, valign=:top, kwargs..., bbox = suggestedbbox))    
+    end
+end
+
+# keyword argument constructor
+function ShapeLayout(slide::Slide;
+    offset_x::Real=20, # millimeters
+    offset_y::Real=50, # millimeters
+    size_x::Real=100, # millimeters
+    size_y::Real=40, # millimeters
+    kwargs... # Forwarded to GridLayout
+    )
+    # Would really like to get the actual layout of the slide here so we can initialize the bounding boxes
+    ShapeLayout(slide, offset_x, offset_y, size_x, size_y; kwargs...)
+end
+
+ShapeLayout(sl::ShapeLayout; kwargs...) = ShapeLayout(sl.slide; kwargs...)
+
+GridLayoutBase.layoutobservables(sl::ShapeLayout) = GridLayoutBase.layoutobservables(sl.layout)
+
+# Make sure that the only things we can add are Shapes and ShapeLayouts
+Base.setindex!(sl::ShapeLayout, content::ShapeLayout, args...) = setindex!(sl.layout, content, args...) 
+function Base.setindex!(sl::ShapeLayout, content::AbstractShape, args...) 
+    # Synopsis: Since shapes are stored as a flat vector outside of the layout we need to make sure it
+    # stays in sync with the layout in case we overwrite. 
+    # We do this by just storing the index inside the ShapeLayoutObservables. If there is something
+    # at the position (given by args...) we just overwrite it instead of adding something new
+    current = GridLayoutBase.contents(Base.getindex(sl.layout, args...)) 
+    slo = if isempty(current)
+        push!(sl.slide, content)
+        ShapeLayoutObservables(content, lastindex(sl.slide.shapes))
+    else
+        shapeindex = only(current).index
+        sl.slide.shapes[shapeindex] = content
+        ShapeLayoutObservables(content, shapeindex)
+    end
+    setindex!(sl.layout, slo, args...)
+end
+
+Base.getindex(sl::ShapeLayout, args...) = Base.getindex(sl.layout, args...)
+
+# This struct exists for these reasons:
+# 1) the contents of a GridLayout must have a LayoutObservable
+# 2) With the current design we need to remember which index we inserted the 
+#    shape into slide.shapes since setindex! allows for overwriting
+
+# Users should not need to interact with it
+struct ShapeLayoutObservables{T<:AbstractShape}
+    shape::T
+    index::Int
+    layoutobservables::LayoutObservables{GridLayout}
+end
+
+# TODO: Need to implement for each shape
+BBox(s::AbstractShape) = BBox(Float32, 
+                            s.offset_x[],               # Left 
+                            s.offset_x[]+s.size_x[],    # Right  
+                            -s.offset_y[] - s.size_y[], # Bottom. Negative since PPTX counts y from the top
+                            -s.offset_y[]               # Top. Negative since PPTX counts y from the top
+                            )
+
+# Don't need to add LayoutObservables since GridLayout has it
+ShapeLayoutObservables(sl::ShapeLayout, args...) = sl 
+function ShapeLayoutObservables(shape::AbstractShape, shapeindex)
+
+    # Just boilerplate to create a LayoutObservable
+    # We only use the computedbboxobservable from all this for now.
+    # Maybe we need to handle a few others for the full API of GridLayoutBase to work well...
+    bbox = BBox(shape)
+    layout_width = Observable{Any}(GridLayoutBase.width(bbox))
+    layout_height = Observable{Any}(GridLayoutBase.height(bbox))
+    layout_tellwidth = Observable(true)
+    layout_tellheight = Observable(true)
+    layout_halign = Observable{GridLayoutBase.HorizontalAlignment}(:left)
+    layout_valign = Observable{GridLayoutBase.VerticalAlignment}(:top)
+    layout_alignmode = Observable{Any}(GridLayoutBase.Inside())
+
+    lobservables = LayoutObservables(
+        layout_width,
+        layout_height,
+        layout_tellwidth,
+        layout_tellheight,
+        layout_halign,
+        layout_valign,
+        layout_alignmode,
+    )
+
+    sl = ShapeLayoutObservables(shape, shapeindex, lobservables)
+
+    Observables.on(GridLayoutBase.computedbboxobservable(sl)) do newbbox
+        updatebbox!(shape, newbbox)
+    end
+    # Would like to connect the sizes and offsets of shape to suggestedbboxobservable so users can change their size
+    # and have the results take effect in the layout, but doing so create an infinite loop. Maybe it can be avoided through
+    # with_updates_suspended
+    sl
+end
+
+# TODO: Need to implement for each shape
+function updatebbox!(s::AbstractShape, bbox)
+    s.offset_x[] = round(Int, GridLayoutBase.left(bbox))
+    s.offset_y[] = -round(Int, GridLayoutBase.top(bbox)) # Negative since PPTX counts y from the top
+    s.size_x[] = round(Int, GridLayoutBase.width(bbox))
+    s.size_y[] = round(Int, GridLayoutBase.height(bbox))
+end